I, too, had a first house (actually a townhouse in Hawaii) where we put down wooden floors, built a small deck (not really, a platform more), other flooring, all the interior paint that we could reach on a ladder (we had an open staircase that needed scaffolding, drew the line there). The house we owned after that was brand-new, we lived there for 6 years, and it never really needed anything until the end of the time we had it. Here, though, the house is 160 years old, and after trying to DIY and realizing even the simplest of paint jobs often wind up uncovering deeper problems, decided years ago to just save up and get it done by the pros. We have a good general contractor we go for big jobs where we (I) insist on having someone registered, bonded, etc. Not only is the built-in insurance an issue, the general contractor knows enough about everything that he comes by and inspects when we wouldn't know if the roofing job, for example, was good unless it rained. He always does things like in the example, he told the roofers to take the leftover shingles we'd paid for anyway and re-roof the potting shed, that we'd paid enough for another day's work.
What we were doing when we first moved here, and tried to DIY, was finding out the job was beyond our (little) expertise, and after buying what we thought was the right stuff, we'd wind up being unable to finish, then paying double; the DIY price and then the professionals.
Another issue was that when we did the townhouse, the jobs were smaller. But the real biggie was that I wasn't working and my husband was still on active duty. He's been retired for quite awhile now, and he has very little patience left. It used to be that I had 60+ hours a week, and sometimes entire days, to do things the way I saw fit. He never complained. But when he works, every little slip is a swearing, angry crisis. When I do something myself, he can think of a better way I should do it. He never complained about the results if he wasn't around to see how I do it.
So, thank heaven for the pros. We have a set of them. Our general contractor. A friend who is very handy does jobs that are eternal in an ever-so-old house. Now if we could just find an electrician (our favorite retired!) for minor wiring jobs!