For myself, the biggest cost to doing DIY over many, many years has been an unwillingness to hire contractors because I know I will do the job better than them.

For myself, the biggest cost to doing DIY over many, many years has been an unwillingness to hire contractors because I know I will do the job better than them. There are a few exceptions: 1. pouring a concrete pad (too dirty, too much work, needs a crew to really be done right) 2. adobe mud plaster (once you've seen people who know what they're doing do that thing, you'll know why) 3. diamond and venetian plaster (same as #2) 4. 3-phase anything (i understand the concept, but that's not enough) but electrical, plumbing, framing, finish carpentry, flooring ... I'm sorry guys, but I'm better and I care more than most of you. What I'm not: faster than you. I'm sure there are amazing trades folk out there who could put anything I do to shame, but finding them and being able to pay them is another story altogether.