I did not build a house, but I did buy a mobile home recently and to save money I did all of the "site prep" work my self. This was basically running a water line (400 ft from the meter), getting electric installed (180ft from the pole), getting a concrete foundation to put the house one (because putting a mobile home on a gravel pad is ghetto and leads to a lifetime of house leveling issues), septic installed, HVAC install (I declined the cheap unit the house came with).

Let me tell you, just those few things were a lot of work. I'd say don't even think about it (building a house) unless you know someone in the business locally that can point you to decent contractors. Let me itemize everything below and explain:

First, I needed to run a water line about 300 ft. I wanted to use all Pex as copper is too expensive and PVC just breaks around here. But after researching, I realized that I'd need a pipe with an inside diameter bigger than 1" to go that 300 ft without a big pressure drop. Once you go above 1" in Pex, you start getting really expensive. I ended up running a "trunk" line out of straight 1 1/4" PVC, 20 ft sections with a 2" bell end. These should be pretty strong and since it is in a straight line, shouldn't break. Every 20 ft, I offset the pipe about 4" to "weave" it into the trench to help with expansion. On each end I used a pvc to pex transition fitting from Sioux Chief. Not really what I wanted, but the pvc was $200 while to do it in pex with a 1.5" line would have been well over $1000. Asking around for tips in plumbing forums does help, but you'll quickly find out that plumbers are very opinionated about what to use (even among themselves) and they don't really like "outsiders" asking for advice. It was a big job, trenching the line took a full day, and then I spent about 3 days cleaning out the trench with a shovel...

Pouring a concrete slab was the next big thing. How hard can that be? Well... I quickly found out that (honest) concrete contractors did not really want to pour me a slab to put a mobile home on since I had no blue prints to go by. This is where having someone in the industry really helps. My family has a auto shop locally and they knew of a concrete contractor that a "rich" customer uses quite often to do industrial buildings. I managed to meet with him, and using some of the ideas and plans laid out from some of the other contractors that turned me down, we were able to design a slab that would be correct to handle the weight and soil movement properly. But through research, I also discovered that concrete needs to be "cured" properly or you loose up to 50% of the strength. This curing is normally not done by contractors. So through more research, I ended up locating and buying some membrane based spray on curing compound that I put on the slab right after it was poured. I think it turned out well.

Septic was fun. This is rural land, so there is no septic service. 30 years ago, this would have been a simple and cheap thing. But thanks to today's regulations, it is now expensive and covered in red tape. Early in my planning, I had a person quote me an install price of $5k for a tank and leach field. I based all of my budget on that. But I never could get the guy to show up, and he would never answer the phone. He was from far out of town too. Using the knowledge of my family auto shop's customer base, I located some people locally, but they all wanted $13k! We went back and forth on prices, I eventually gave up and went back to trying to find shady craigslist people again, but I still couldn't find anyone that would show up. Plus the local guys were all telling me there is quite an epidemic of unlicensed installers that will do cheap work under the table but once the county finds out about your bootlegged septic install, they'll make you remove it and have it re-done. Basically a bootlegged system carries the same punishments as dumping raw sewage into a river, so it is not something to screw around with as you are dealing with the state's health department. In the end, I paid one of the local guys to do it right for $13k...

HVAC systems I am somewhat familiar with, so I was fine with just looking around locally to find someone that is an approved dealer for the HVAC brand I want.

The electric connection from the pole to the house was not so straight forward though. Most connections from the meter to the house are under 40 feet. I was at 180 ft, which meant I had to up size the wire. Which also meant I had to up size the conduit it was in to 2.5", but the conduit into the house would still be 2". So basically I ended up installing a feed through sub panel in the back yard. Run the bigger wire to that, then for the last 20 ft or so, run some smaller wire. But all this had to be researched quite a bit on my own. Talking to electricians didn't help too much surprisingly. Thankfully we did have one in my family though.

So as you can see, even simple tasks that you might think you can do by yourself, end up not being as such and/or taking 4x longer to complete (and maybe even 4x more price-wise)

As far as concrete constructed houses, ironically, one of my family members lives in one. It was built in the 1970's. It arrived piece by piece on a several trailers and was assembled with cranes. The walls are solid with no insulation. Even in our hot climate where most people's electric bills are $200+ in the summer, he normally stays below $100 surprisingly, though he does live under a thick cover of trees. He's had some rather large tree branches fall on the house too, but it didn't hurt anything other than break some of the stone/spanish tiles on the roof. Interestingly, his insurance is not cheap. He has to pay a premium for "unconventional" construction for both flood and fire insurance even though water or fire would not bother the house much...