[HTC Rezound] Scott:
Dude, these are the same questions I ask myself on a regular basis... I will say that 90% of the time that people say they followed the instructions to the T they did not. People also don't like to set there phone up after a FRESH install so they dirty flash the phone and then they dont realize that apps get updated during different versions of a ROM build. This can cause changes in the database and then lead to corruption. This corruption can then lead to endless issues. Nice times out of 10 I tell people with odd one off problems to wipe and re-install and the ROM and Bam! Just like magic the problem is no longer present. Just from the issue they report I can tell you if the did not wipe or if they tried to restore something back up.

As far as the variances in heat and battery; well thats a vary hard one to pinpoint. But I have it narrowed down to a few factors....

1. Dirty install / restore from back. As noted above; when you have a corrupted DB it CAN cause the app to "run away" leading to not only unstable and unpredictable results but battery drain also. I am not sure how often this is the issue but I can guess maybe 1/3 of the time.

2. Not all phones ARE created equal. HTC, just like any other mfg, uses parts from the lowest bidder. Case in point is the 3.7 vs 3.8 volt battery issue. My guess is they prolly spec'ed the device for 3.7v and when some battery company said we can sell you some 3.8v batteries at half the cost you pay now they jumped on it. Any company would. The purchasing department did not talk with the engineering / development depart and now we saw the aftermath on the earlier ICS leaks. The 3.8V batteries would not charge. This means HTC needs to fix the kernel to compensate for the variances. I think they did this in the most recent two builds because I have not heard any complaints lately. Other factors can include different screens. Thats a big one. If the screen is supposed to draw, lets pick an arbitray number because i dont know the real values; 100mah and they get a deal on some that draw 120mah guess what... That variance will cause battery drain and heat. Anything that causes battery drain will cause heat. Thats just basic physics. On the LG Optimus S, my first Android phone and first CleanROM ever, there were two differnt LCD panels being used. This caused problems with Recovery but no the OS. People who booted into recovery with who had on panel everything was fine and dandy, those who had the other panel had no display. So this was fixed by the REcovery gurus doing what it is that they do.

3. Apps that do not play nice. I think this is a big one as well. Now add that to point #1 and Point #2 and you have a genuiine recipe for disaster.

4. Usage patterns. I say my usage is light. IM not going to explain what I do because thats not the point but the next guy says his usage is also light but yet his screen on time is 4 hours and he is using tether for 6! So you can see the expectations are based on usage and everyones usage is skewed based on what they think is a usage pattern. The same can be said for "heavy" users. Some poeple claim to be heavy users when in fact they are a light user and have similar usage habits to me. This will always be a point of contention and no one will ever sit down and make a chart of how you use your phone and what your battery life is because of all the above points and the fact its a purely subjective measurement.

5. As noted by krelvinaz; location can have an impact as well. If yoru not getting good signal the phone is going to need more power to pull in the weaker signal. More work = more power = more heat. Simple physics again. Example; when I visit my Dad on the east coast I got horrbile signal. He lives in the Berkshire mountains. I barely got a signal at all and it killed my battery. Recently they put a VZW tower nearer to his house and now I visit and good good battery. Location can be a factory.

Anyways, take all this with a grain of salt because I only have one Rezound and therefore cannot test anyone elses. I am also a "light" users. I use it develop on. If its not in Recovery then I am prolly sleeping, lol

Anyways.. Hope this sheds some light from a ROM Developers perspective.

EDIT: I also want to state that all of the above being true only if the ROMS installed are all exactly the same. You can really Ef up battery life by doing things in the ROM that dont quite work out the way they are supposed to but that is a completely different issue all together.

They are not tall tales. I get that every single day.

THis is very true.

Agreed, see above.

Damn... Thats not a bad idea! I think I will start working on it! lol

Good post OP!

-Scott