Me and my partner rebuilt a log cabin into a year-round house over the period of a year. Only bearing walls remained. Re-insulated, expanded and changed the roof, added a bathroom, sleeping lofts, etc. She did most light work while I was holding down the day job to secure the down-payment and mortgage, and I would handle the heavy stuff on the weekends.
The zone is not ideal for wind or solar, so we are connected to electrical. We had a contractor help with bath tiling, he did plumbing and electric hook-ups, an electrician did what was required by code for the electric system.
Every single one of the licensed pros had cut corners.
The electrician did not secure the outlets to the walls properly, just enough for them to start getting loose after 2 years. One weak screw instead of four. I was afraid of electric for a while. Only had the energy to read the code, some books and watch some youtube videos and re-secure all the outlets and set up 2 extra outlets, with channel cable dragging, etc, about 3 years ago.
The plumbing had multiple mistakes as well, wrong tank positioning, wrong main drain placement, no main cut-off to the tank, did not get a filter hook-up or a drain valve, etc, and the hot water boiler did not get a proper set-up for easy maintenance (the magnesium sacrificial anode cannot be removed, too close to the ceiling, you have to dismount the whole unit).
If I had the money and not to have to work during the build process, I would have built a small house first, learning everything about how to do it right and observing the "pros" as they go along. But hey, we have a house that total spend was 1/3 of the market, enough land to build a second one, and I am a different man from the experience.
It was my first experience with engineering outside of software. Trust no one, do your own research, plan, experiment and verify apply even more in "physical world" engineering.
It's nice to become more and more self-reliant with construction skills. I just serviced the indoor plumbing, changed 3 taps, installed a water-filter hook-up and filter, including pipes, and plan to assemble a big water filtration system, myself, in the summer. $ 5K to 7K for filter tank, controller and installation by contractor, vs $600 for system and medium from manufacturer, and install it yourself.
Whether you plan to go off-grid, build, be your own general contractor, or even just buy a property, doing things yourself, provided you can follow engineering principles and values, is always the best bet. You want reliability. The pros want to make a profit.
Life pro tip - if planning to participate in construction in any way, audit the locality and how strict vs smart their code and inspections are.