A buddy of mine is a fire chief. In his town, if you do any type of remodel it needs a permit and inspection. AND - you have to install smoke detectors up to code throughout the entire house! (New deck, new detectors! I think they even have to be smart ones where if one goes off they all go off).
He said they had one fire where they had a contractor do a remodel including a fireplace. The contractor was supposed to get the permits, inspection, etc. (They didn’t)
The homeowner lit the fire once everything was done to burn off the new paint (and smell). And then went to the far end of the house to watch TV as they didn’t want to be in the room that smelled.
Pretty soon they smelled something different than the faint smell of paint. A faint smell of burning wood maybe? The man wandered out to see his new den in flames. Got his wife out, called 911 and watched as most of the house was destroyed. I forget exactly, but the fireplace was designed for a two-inch air gap, but the contractor had put it up against the framing.
My buddy didn’t mention no insurance coverage. But the guy did get fined for no permit, another for no inspection. And a third for no updated smoke detectors. (He didn’t have ANY in the house!)
True. I was too hasty to throw inspection into the mix. One should still get an inspection for new electrical even when not using a contractor. This presumably applies to new water lines. IIRC in my jurisdiction a repair of an existing electrical line/socket/etc or water line does not need inspection.