Ivestment, running cost and durability of goods - Page 1
Forum section: electronics / general

author: Brutte
author_rank: Frequent Contributor
timestamp: August 08, 2016, 01:11:15 pm
content: This is a decision-making question, inspired bythispost.Imagine you have to make a decision whether to buy a cheaper and less durable item of higher running cost or alternatively a more expensive, more efficient and longer lasting item, a tool, a car, an asset, whatever.From infinity of decision parameters:pis a year running/service cost[$/year],qis periodic investment cost and shipping[$/r],ris the durability after which you buy next identical item for q.sis the color,tis.....lets simplify and imagine only initial three factors [p,q,r] play role while all other factors [s,t,..,z] are same/similar for both assets you consider thus those haveno influenceon your decision. Assume youa-prioriknow [p1,q1,r1] for "Chaina" and [p2,q2,r2] for "Weller" for you (pick reasonable ones).What is your choice? Can you give your example of two triples that are atiefor you? (tie = a bordering case)Just as an example, I would consider "Weller" [1,150,20] to be a tie with "Chaina" [2,20,3] and I would not prefer one over the other under assumptions mentioned above.Remark1: My English is a bit Chinglish so be warned.Remark2: The purpose of the topic is to calculate yourtime value of money

author: FireFlower
author_rank: Regular Contributor
timestamp: August 08, 2016, 04:47:47 pm
content: It is easy when you just run numbers and the product that you're using won't end up to your end customers who furiously find out it is breaking down too much.So lets say you want to buy quality hot air guns for your company. Lets say you have 5 people who need hot air stations.We use daily our hot air guns a lot, oldest one is from 2001 and still have not replaced the heating element or anything else has not been done for it.We mainly have just JBC hot air stations. Models vary a bit as years have gone by, we have needed a few moreFor example these:Each of these costed about 1200-1600€ brand new. We have bought one replacement heater element but its still waiting to be used. So lets say one unit costs about 1350€ to buy as brand new and you have 6750€. Lets assume "Chaina" brand is able to do same job as efficient as JBC but how often it has to get broken you could say JBC would be better investment? So running numbers we can assume JBC probably lasts 20 years without need for repairs. So we divide 6750€/20 years and we get 5 units cost yearly 337,50€. One unit would be 67,50€.So "chaina" brand would have to last in actual production enviroment longer than one year to be better investment than hi-quality JBC.Of course this is over simplified, you also have to consider it is actually ESD protected product and can handle 24/7 use.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 08, 2016, 05:52:33 pm
content: Quote from: FireFlower on August 08, 2016, 04:47:47 pmThanks for the input.I do understand that real life decisions are more complicated than just three factors I have mentioned in opening post but putting fourth, fifth,.., eleventh etc decision factor into this topic just won't help us to come to any conclusions. That is why I want this topic to bestrictlylimited to [p,q,r]. The other factors are indistinguishable and that is the assumption.QuoteOk, that is [0$, 1350$, 20 years] for your JBC tool, no servicing or spares.QuoteNo, breakdown is spontaneous, random. And from your post I can see you are highly subjective and far from "Chaina"Again, as in opening post, lets simplify and assume a-priori each asset wears-out after r years. No surprises. After r years you just toss it to the bin and order new one on eBay, not going into details of its mean time between failure statistics.QuoteOk, so your Chaina is [0$, 67.5$ ,1 year], no servicing or spares.Thanks for your tie.Lets see what others think, how they trade durability for investment cost and running cost.Of course the topic is not about hot air station and country of origin but about assets.May be a car, may be a scope, may be a software license.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 08, 2016, 06:45:28 pm
content: Quote from: blueskull on August 08, 2016, 06:21:10 pmThis is [0, 120$, 5 years] for Quick 975DW in a tie with [0$, 1999$, infinity] for hypothetical "Eternal Weller".

author: Brutte
author_rank: Frequent Contributor
timestamp: August 08, 2016, 07:26:58 pm
content: Quote from: blueskull on August 08, 2016, 06:59:43 pmThere is a difference when you spend 120$ every 5 years or 120$ once every 10 years. So [0,120,5] must not be in a tie with [0,120,10] or with [0,120,infinity] as it makes no sense.QuoteWell, in the context of the topic it does not matter how you use the assets as long as both would serve same purpose. Obviously same item for you lasts for 5 years, for Joe that lasts for 7 and Jane wears it out in 4. However the topic is not the Weller endurance question but your economic preferences (just to get you back on the topic).I was asking about your [p,q,r] that is in a tie with your [0,120,5]. Would you consider [1,100,4] a tie for example?Etc.

author: dannyf
author_rank: Super Contributor
timestamp: August 10, 2016, 11:10:56 pm
content: One way to do it is to use npv.The example, however, is highly simplistic. If you introduces other elements, like probability of break down, replacement risks, ..., it becomes more complex fast.But as a first order approximation, consider two choices: buying quality and buying cheap. Depending on ones subjective evaluation of risks and expectation of the future, it is entirely rational for one to buy quality yet another to but cheap.Something nerds rarely understand.

author: station240
author_rank: Unknown
timestamp: August 11, 2016, 12:35:51 am
content: I prefer to use the other method, if the device fails, what does it cost in time/money/annoyance to replace it.Eg something like total cost of ownership over 5 years.So you find things like:1) 30 days to get a replacement shipped from China, unless you ordered two to keep a spare (2x the price)2) Cost of buying two cheap units is near or above the cost of one decent one.3) It's your hobby project, so you just don't work on it for 30 days, then forget what you were doing next and put it back in the drawer.Personally I think accounting is what is wrong with today's manufactured goods. Give workers decent tools, decent wages and have someone sanity check what the engineers barfed up before it goes into production. Result you get better made goods, loyal customers and less issues with assembly. Naturally Accountants haven't figured out how to price any of these things, so you end up with shit like 0.2c resistors used when 0.3c ones were specified.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 11, 2016, 01:12:00 am
content: As you have stated your question there is a slight numerical advantage to one approach. You seem to be inquiring into something beyond money, psychology or something.For that, a better question would be: Do you prefer a (0,100, 10) product, or a (0,20, 2) product? All other things being equal. I think I prefer the (0,100,10) product, but when I start to think about why they are things that violate the premise (all other things aren't equal).

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 07:43:53 am
content: Quote from: dannyf on August 10, 2016, 11:10:56 pmA case where the asset wears out and does not break statistically is not that far from real life as you might think. Perhaps in the context of a "Chaina" one may be biased by personal negative experiences and additional cost that reflects disappointment of shortror other losses (a delay waiting for new item). That disappointment and other factors were ruled out in the first post - assume youa-priori know rand pick two pqr sets that are a tie for you.I do not know how to express that in English more clearly. Think about "Chaina" and "Weller" in a symbolic way, not the biased american way. It could equally be a diesel or petrol choice, when you are buying a car. Diesels have lower running cost with longer service intervals (lower p), however are more expensive (higher q) but are also designed to do more millage (thus longer r) than petrol (typically). Ok, it may be that diesels are not that clean but imagine you ignore that and factors other than pqr.QuoteBut as a first order approximation, consider two choices: buying eco and buying cheap.Yes but your "quality" contains twenty factors that are taken into consideration while making decision. If you were to know people's choices w.r.t. the Chaina/Weller subject, I think three factors is an adequate number.In my opinion the pqr set and the assumption about a-priori wear-out in r is not "highly simplistic". It has a serious advantage over your [p,q,quality] or other [p,q,eco] in that it allows understanding/infering the core of economic preferences w.r.t. Chaina/Weller in an easy and unbiased way.T.B.C.

author: Brumby
author_rank: Unknown
timestamp: August 11, 2016, 09:15:56 am
content: Situation is important.If my hobby setup has a key element fail, I am likely to not be impacted too much - and may even have an acceptable, if not ideal, workaround. A production environment is more likely to suffer significantly.Thus, I could go for the cheap end of town and risk repair/replacement because it's not a major impact - or I could go up-market if the budget is there.Which way any person goes will depend on their unique experiences.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 11, 2016, 10:01:37 am
content: I think this is an academic question, given that the value of 'r' is almost always unknown.If you can come up with a reliable way to determine 'r' without actually buying and using a large, representative sample of units and performing an MTBF analysis across them, then you're really on to something.For the sake of argument, suppose it correlates positively with cost, which in my experience isn't true nearly as often as I'd like.Then, it's down to how often I expect to actually need something, and whether it's a capital expense that my business needs to pay for, or whether it's something that's job specific and can be billed to the client.If I know I will, or am likely to, use a product regularly, then I'll usually absorb the cost into the business, and buy the higher cost / higher quality item. (Note: 'quality' does depend on s, t and so on, because I never know 'r').If it's job specific, and will likely just take up space once that job is complete, then a lower cost item makes sense, provided it'll do what it needs to do well enough. In this case I don't really care about 'r', even if I could know it.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 10:21:08 am
content: Quote from: station240 on August 11, 2016, 12:35:51 amWell, thanks for the hint for a new pqrstuvwxyz topicThis one stays pqr only.Quote from: Brumby on August 11, 2016, 09:15:56 amNo, it is not. Read opening post:lets simplify and imagine only initial three (p,q,r) are distinguishable for youJust to give some examples: imagine you pick hot air station and make the decision includingswhich is the color and you are color blind. Or you pick a truck for your company, candidate diesel truck top speed is 140km/h, petrol version top speed is 139km/h while the car is used for local distribution of groceries ONLY.QuoteRead the opening post. I think you did not uunderstand whata-prioriassumption is.Ok, we need another example.Imagine you do some hobby stuff,exactly same thing, with same hairdo and lifestyleas 100 other eevbloggers. Half of them use "Chaina" and half of them use "Weller". All the "Chaina" guys report the asset wears out after exactly r=3 years while the Weller wears out after exactly r=9 years. This does not change over course of time.Would you consider [0,400,9] a tie with [10,120,3]? And that was my question.I am not asking you to buy 1000 Wellers and test that for r prior taking decision! Assume you know [p,q,r] a-proiri and after that r you are forced to buy a new one.Time for next example: imagine this is a software license that expires after r years and you a-priori know the r. Hope this is that less biased than "Chaina" and "Weller". Would you expect r to be, as you suggest, "almost always unknown" in case of software license? Would you expect that r to be statistically uncertain and even though the license agreement was for 2 years, to expect it to "wear out" sooner?Nothing beyond pqr is important in this topic.That is the assumption.

author: Brumby
author_rank: Unknown
timestamp: August 11, 2016, 10:39:10 am
content: Quote from: Brutte on August 11, 2016, 10:21:08 amYour premise is fundamentally flawed.SituationISimportant.Not only is it important, it would seem to be essential. It is the ONLY factor that allows for any value to be assigned to the three attributes you have isolated. Without a means to evaluate, how can you know what is important? How does someone come up with the numbers you ask for?If you were to take samples of 1000 people's answers and then plot these against their 'situation' parameter (industry, interests or whatever), I bet you are going to find a correlation.Feed those numbers into some statistical number crunching and I believe you will find you could deliver some statistical predictions of the three parameters you've isolated, based purely on 'situation' ... with the usual one sigma, two sigma, etc variances.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 11:15:08 am
content: Quote from: CatalinaWOW on August 11, 2016, 01:12:00 amYes, you are rightI was asking about a tie because of a reason.What I wanted to poll was yourtime value of money.Unfortunately I cannot ask you directly about time value of money you use in your every day decisions because of biasing reasons. That is why I am asking about a tie that is made under assumptions from opening post. From that it is quite easy to calculate your time value of moneyAnd I will show you how to calculate that later.QuoteI do not agree, that is not a tie. Don't you know what tie is?Wikipedia - Tie.I would like you to proposea tie, two equally preferred pqr sets. And pick any asset that suits you best. If you do not solder, don't pick hot air station! Could be anything, a washing machine, could be a DC/DC converter, could be a compiler or a bike. But please do not write that [0,100,10] is in a tie with [0,100,5] under given assumptions because I already know (I assume) you are rational.QuoteAgain, I was not asking you what you prefer! I was asking about your tie!Of course I can infer (from the context of your post) that you have shown a bordering case, then:if ([0,100,10] > [0,20,2]) then just maybe ([0,100+1,10] == [0,20,2])but I would prefer to avoid that "just maybe". Give a tie, not "I would prefer..".BTW, even [0,100,10] == [0,20,2] is irrational under above assumptions because your time value of money becomes 0First I will calculate time value of money for other ties posted in here.Later on I will post how to calculate it by yourself but for now I do not want to post the equation itself because I believe that could bias some answers.

author: Kilrah
author_rank: Unknown
timestamp: August 11, 2016, 11:41:52 am
content: I don't see how a "value of time" can be inferred in any meaningful way from your p,q,r sets, given that nothing in those relates to time spent in a deterministic way. Even less how all other factors can have no influence.As Brumby said, it's so grossly oversimplified that it just doesn't mean anything. One simply would not choose between A and B based solely on p,q,r without considering r,s,t so the whole situation isn't even a thing. It's rather even backwards, given p,q,r are rather a secondary concern that you'd only start looking into once you're satisfied with r,s,t.

author: Brumby
author_rank: Unknown
timestamp: August 11, 2016, 11:47:09 am
content: Quote from: Brutte on August 11, 2016, 11:15:08 amTherein lies a fundamental issue.My 'time value of money' is very dependent on situation. It is different for my role as a professional, a consumer, a volunteer, a family man and a hobbyist. There is no one set of parameters I could give you without some sort of qualification.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 12:34:04 pm
content: Quote from: Kilrah on August 11, 2016, 11:41:52 amIt is not "value of time" but "time value of money"And it does not refer to your time spent anywhere but the relation in between some value today and same value tomorrow. This quantity relates idea of a value over time. Read the Wikipedia article I linked or google for "time value of money", "interest rate" or "rate of return" as these all are related.I do understand these are abstracts and it might be tough for someone to understand how come some people prefer to invest more for longer (Weller) while some prefer to spend less but for less endure assets with higher running costs (Chaina).Quote from: Brumby on August 11, 2016, 11:47:09 amWell, if you can apply simplifying assumptions from opening post to your professional life (buying a machine), a consumer (buying a washing machine), a volunteer (buying a server for your organization) and a hobbyist (buying a hot air soldering station), if you are rational and want to spend the money for the profit of your company/family/organization/hobby then I bet your time value of money is the same in all above cases. If you cannot imagine you know a-priori the exact pqr for some asset, I cannot help you and you probably have to find some other way to find out your time value of money.Of course here we might come to the speculation what happens when you do not like company you are dealing with, you do not respect the non-profit organization you were forced to work for escaping from jail, you question whether your family deserve decent gear when you are planning to leave them soon, is your electronics hobby worth it when you are burned out (pun intended), etc.But I believe that if you are a rational person, your time value of money is consistent over all your decisions you makewith your money.

author: Kilrah
author_rank: Unknown
timestamp: August 11, 2016, 01:33:37 pm
content: Quote from: Brutte on August 11, 2016, 12:34:04 pmAh, misunderstood what you were talking about. But while the concept is different, the probelmatic is the same. It depends on what kind of product you're talking of, the purpose which you intend to use it for, the current market trends, and quite a bit on just luck...On your soldering station, I'll take a pretty good one I intend to last long becasue there are no short term prospective improvements in soldering stations. If I need a PC TODAY for some application that isn't very demanding, I'll buy a $300 piece of crap that can just keep up with doing the job for a few weeks because the next computer I actually want to invest in is the next Macbook Pro generation which is supposed to come out in 2 months.The faster things are evolving and the less you're using them the least you'd be likely to pay, so the pqr ratio does depend on intent and situation.Then:Quote from: Brutte on August 11, 2016, 12:34:04 pmWell, you can NEVER know the exact pqr for any asset. You can only rely on an estimation with a very dubious accuracy and which might be completely wrong. Which is why pqr should only be a part of your evaluation, and typically a relatively small one (as I said earlier, it's a secondary concern).You can buy a top notch device (supposed to be durable, no maintenance) and it fails the day after the warranty ends with prohibitive repair costs, just as you can buy what seems like a cheap piece of crap that's still running strong after 15 years. I've personally experienced both.You can buy the best thing there is for your company that you intend to keep for 10 years and pay $100k for, and 6 months later someone comes up with a new product that is 10 times better for $20k and that instantly makes your investment obsolete, in which case getting a cheapo stopgap solution for $10k would have been a better decision. You have no control over that, and again any estimation/analysis you could do to help you make that decision doesn't depend much on pqr.Your method could have worked several decades ago when options were limited and it was typical to stay with a supplier/company regardless of anything that was offered elsewhere, but nowadays it makes no more sense, there are way too many other factors to consider and it would be poor management not to take them into account, or at least try to to the best of your abilities.

author: Brumby
author_rank: Unknown
timestamp: August 11, 2016, 02:09:15 pm
content: "With your money"This is getting a little more descriptive - but even there, I must say that my view on business funds, family funds and personal funds are not identical ... and that the time value is based on different criteria. As an example, in a business situation, time values are a composite involving various individuals and circumstances - whereas personal hobby values are much lower.I'm still not convinced about the objective here, but I'll step back to see how it pans out.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 03:36:06 pm
content: Quote from: Kilrah on August 11, 2016, 01:33:37 pmCould you be more specific which of my paragraphs was not precise enough? This way I would have the chance to improve.I try to reference various terms and support those with "101" examples but I am not a native English writer so perhaps here lies the "misunderstood" problem..QuoteNot sure if I understand correctly.When I start the opening post with "assume a situation you suffer color blindness, would you pick Weller [0,400,9] or Chaina[10,120,3]" and you ask "What is the color of the handle, I cannot make a decision without knowing it" then well... clearly that is not a topic for you. This one works only for an a-priori known pqr and irrelevant stuvwxy and z (b.t.w. color is referenced ass).I have lost the count of how many times I have rephrased that.I do not know what environment you represent, lets hope you are a mechanical engineer...Example just for you: imagine you face a decision to buy an asset that wears out after r years (a precision wrench that is certified for 3000 nuts and your company does 1000 nuts a year) well you can assume there could be some chance there is going to be a time warp near where you live then and there is a chance one per zillion an asset would last for 4 years, however there are higher chances you are faced to buy another wrench after 3 years.QuoteI am not asking you to pinpoint the pqr of Weller or Chaina somewhere in the future. I am asking you to assume some reasonable pqr pair that gives a tie for you.Quote from: Brumby on August 11, 2016, 02:09:15 pmNot sure how one can interpret opening post:QuoteIs my English that bad? Any suggestions on how should I rephrase that sentence?

author: Kilrah
author_rank: Unknown
timestamp: August 11, 2016, 04:18:35 pm
content: Quote from: Brutte on August 11, 2016, 03:36:06 pmI'm not native English speaker either, so it could have been my understanding too.Quote from: Brutte on August 11, 2016, 03:36:06 pmThen it's a topic that isn't for anybody. Your hypothetical situation of not considering anything other than p,q,r means it doesn't apply to any real-world situation. It makes no sense to consider things that way. Nobody can make a sensible decision with only p,q,r. stuvwxy are the factors that will define what pqr compromise is more appropriate in a given situation.Quote from: Brutte on August 11, 2016, 03:36:06 pmWhat is this tool used for? If it's used exclusively to produce a product that we'll stop manufacturing in one year I'll probably choose a cheap tool with a life expectancy of not much more than a year because I know its extra potential won't be realized when the tool ends up forgotten in a drawer in a year from now, and would be pure loss.If it's a tool that we'll use regularly for the foreseeable future and that will never evolve then I'll pick one that's got a lifetime warranty even if it costs more.If it's a tool that we'll use regularly for the foreseeable future BUT that's likely to be obsoleted in 3 years due to improvements in that class of tool, then I'll pick one that's amortized in 3 years so I can change for the best tool as soon as it's available without wasting potential on the old one.See how context is essential?

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 04:43:27 pm
content: Quote from: Kilrah on August 11, 2016, 04:18:35 pmAt last we agree at some point!Did you really think this topic and its assumptions match the the most generic decision scenario everybody on this planet has already made and will ever make in most distant future??Quote from: Brutte on August 11, 2016, 03:36:06 pmQuoteSorry, no. But I am curious about opinion of others.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 11, 2016, 05:47:24 pm
content: Time value of money was one of those other factors I was told to ignore. This is an interesting set of questions because of the insight it provides in the difficulty of doing unbiased polling. You stated that my two examples were not a tie. Which is true only if other factors such as time value of money are incorporated. Your addition of a 1 in the p position breaks the tie, but does not of itself provide information on the time value of money other than sign (I can imagine situations where the time value of money might be negative, but in those cases the details are far from your biggest worry). If you had a slope of how this comparison changes as p rises you could get a numerical value for time value of money. This value would, as others have pointed out previously, not be an absolute or invariant value, but would reflect the situations envisioned by those answering the poll. Time has a very different values under a variety of conditions.It is much like maintenance. Clearly it has great value. But if current economic conditions mean you are barely making payroll, or paying suppliers, the value of maintenance is zero. Because if you do pay for it, the money invested will benefit the other folks that pick over the carcass of your business, not you.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 11, 2016, 06:19:37 pm
content: Quote from: CatalinaWOW on August 11, 2016, 05:47:24 pmYes, I was asking about a tie (equality in between two choices) while you provided inequality:Quote from: CatalinaWOW on August 11, 2016, 01:12:00 amOf course I could exchange single question about "give me a tie" into an essay, a series of Q&A:Code:I know you prefer (0,100,10) over (0,20,2). Let me ask you further question:Now do you prefer (0,101,10) over (0,20,2)?If your answer would be: "Still YES, I am for Weller" I would ask you another question about (0,102,10).If it is being still better over (0,20,2), wait for your answer and if that is still YES then there goes (0,103,10), then 104$,....,1565$ and I would be hoping that at some q and same r=10 years you would have to drop the dreams about Weller, even though it lasts 5 times longer than Chaina.But instead of continuing the lenthy set of Q&A I was hoping that asking about single tie is a better solution.QuoteSorry CatalinaWOW how can it break a tie when you have not posted a tie??Quote from: CatalinaWOW on August 11, 2016, 01:12:00 amHere where I live when someone says that s/he prefers apples over oranges then it most likely means these are not equal for him/her..Is this my English again?

author: nctnico
author_rank: Super Contributor
timestamp: August 11, 2016, 07:58:30 pm
content: Quote from: Brutte on August 08, 2016, 01:11:15 pmI think you forgot the most important factor: 'how well does it work'A crap tool no matter how cheap or expensive it is is still a crap tool which is cumbersome to work with and results in less than good products. So you need to introduce factor a: value for money. Only after value for money has been evaluated you can look at the TCO (total cost of ownership). It is pretty similar to buying a car. First you look at what size you need, what kind of driveability requirements you have. There is no use to buy a 2 seater if you have a family of 4 or a car with a weak engine if you want to haul a big caravan. From there you can create a short list with models which fit and then look at things like known issues, durability, repairability, etc which influence TCO.

author: Kilrah
author_rank: Unknown
timestamp: August 11, 2016, 08:00:47 pm
content: Quote from: Brutte on August 11, 2016, 04:43:27 pmNo we don't, at all... you say it isn't a topic foreverybody, but I say it isn't a topic foranybody.In my opinion anyone who'd answer your question in the way you want would only be doing so only becasue they're missing a huge point which is the importance of what you don't want them to consider, aaand... missing that point would mean they're not a position to answer the question in the first place.I'd love to be proven wrong though, I'll also be following.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 12, 2016, 02:44:40 am
content: Quote from: Brutte on August 11, 2016, 06:19:37 pmI completely agree. When someone says they prefer apples over oranges they are not equal. But your problem statement said that only three decision parameters were to be considered. If I am asked my preferences between apples and oranges, but allowed only to compare whether they are grown on trees or not, whether they have seeds, and whether they provide nutrition, I can't explain the differences which cause my preference.Perhaps it IS an English problem.In your question you give two choices, one which has high cost and long life, the other which has lower cost and lower life. The values are chosen such that after the life of the longer lasting product, replacement costs for the shorter life system will make the total acquisition cost is the same for both systems.You then assigned a small operating cost to the lower cost system. In this mind this makes the two systems not equivelant. Imagine two high cost systems, Weilar 1 and Weilar 2. p, q and r for the two systems are (0, 100, 10) and (1, 100, 10). There is no question in my mind. Weilar 1 is the better system. This isn't a tie, and it has nothing to do with the acquisition cost or longevity.Perhaps you were trying to apply the costs of purchasing and installing the lower cost system repetitively over the time period to the operating costs. That is not how I interpreted your question, and why I proposed an alternative set of scores to compare. That cost of replacement in two otherwise equivelant systems is why I would tend to prefer the longer lasting systems, but again, you stated that s, t, u .... was off limits.

author: Assafl
author_rank: Frequent Contributor
timestamp: August 12, 2016, 05:34:04 am
content: PQR is probably most important for some things - say water pipes in a new apartment. You want r to be long and are willing to pay for it.But as one covers these basics other parameters can take precedence. For example, a cheaper soldering iron may make good financial sense but can not solder a ground plane.For some things r is not important. Such as cars, where a Mercedes isn't that much better than a Toyota. But Mercedes has bling and manufacturing inefficiencies that work up the cost.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 12, 2016, 07:47:26 am
content: Quote from: nctnico on August 11, 2016, 07:58:30 pmNo, I have not."How does it work is"ufactorQuoteSize isvQuoteThe engine power iswI could play that all day long..Once again, all factors beyond pqr do not influence your decision on choosing Weller or Chaina. That means that from what you choose these stuvwxyz factorsare equal for you for both considered assets. Not to be confused with "are equal for anybody" because I have given an example where chosen trucks run 140km/h and 139km/h so clearly are not equal w.r.t. top speed but this difference becomes irrelevant in your case of grocery distribution where you won't pick faster truck even though it is faster because it would never reach even half of that speed during its lifetime.So in your case anduboth do the jobyouare planning to do indistinguishably well, in case ofvboth meetyourrequirements, in case ofwno difference that would make Weller better than Chainafor you, thexis also pretty much whatyouexpect,yis ..... well wait.. nope still no dice.What about z? Canzbe a decision factor? Damn it, same again, both Weller and Chaina have samezforyou.Only those pqr factors are different..QuoteOk, I have run out of letters, there is nothing beyondz..Now I am forced to use double lettering to mark your newly proposed decision factors.Lets name:-known issuesasaa.-repairabilityasab-youretcis going to be a list of factors fromactogjso irrelevant/indistinguishable factors are now: s t u v w x y z aa ab ac ad ae af ag.....gj (to be continued)Ok, any further questions?Some important factor missing on the list?If not, what is your pqr tie foryourfamily car?

author: R005T3r
author_rank: Frequent Contributor
timestamp: August 12, 2016, 08:06:13 am
content: In my opinion you should not be brothering about this if you are a hobbyist: you do electronics for hobby, or for having a great time, it's fine if you can afford that: it's up to you how much you are going to spend on it... If you are a businessman, things changes quite radically: you are there to make money, not for your amusement! So, you want to compromise between price and durability. Also you want to be sure to have the things serviced fast (as you can continue to work) and find replacement for your equipment.In my opinion: decent brand + decent amount of money = you can't go wrong. I would avoid "super high end" instruments because they are designed for certain specific applications and they are certainly not suitable for the major work you are going to do at home...Problems are unpredictable by nature and you never know when a problem or a malfunction will happen, however If you have a crappy instrument, you can be the best skilled person in this world and you will end up with a crappy job, that's another thing to consider!

author: Kilrah
author_rank: Unknown
timestamp: August 12, 2016, 08:21:27 am
content: Quote from: Brutte on August 12, 2016, 07:47:26 amThere are 0 chances for 2 products to satisfy all those requirements in the exact same way and thus ONLY be distinguishable through their p,q,r, so again the question makes no sense. There is ALWAYS something other than p,q,r that matters.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 12, 2016, 08:26:39 am
content: Quote from: Kilrah on August 11, 2016, 08:00:47 pmSorry, what is the difference in between those two statements, with respect to our subject?I am not a native English writer and google translate returns same semantic meaning of both sentences....More or less: "Not 100% of Earth population finds this subject interesting." I am puzzled.. Any reference?QuoteOk, thanks, I have to think your remark over.

author: Kilrah
author_rank: Unknown
timestamp: August 12, 2016, 08:30:00 am
content: Quote from: Brutte on August 12, 2016, 08:26:39 amYours is "Not 100% of population can answer that". Mine is "0% of population can answer that".But if that's causing trouble in understanding I guess we won't go anywhere.

author: Brutte
author_rank: Frequent Contributor
timestamp: August 12, 2016, 08:57:13 am
content: Quote from: Kilrah on August 11, 2016, 08:00:47 pmHere is thegoogle translate linkfor "it isn't a topic for everybody".Here is thegoogle translate linkfor "it isn't a topic for anybody".Just pick your language.Ok, thanks for your explanation but for my language both return exactly the same semantic meaning.If, as you suggest, both those sentences have opposite meaning then I am afraid all of my previous posts are infested with similar contradictory statements.No wonder you guys have difficulties in deciphering my thoughts.....

author: Kilrah
author_rank: Unknown
timestamp: August 12, 2016, 09:11:25 am
content: Google translate is hopeless for running a conversation.Just find a random webpage and have it translated, you'll see how many dozens of mangled sentences come out of it. You can usually understand the context, but detail is lost.