It depends on the item and the risk. Google/internet has helped here immensely. My refrigerator 'failed', and it just needed a new logic board. Way easier than

It depends on the item and the risk. Google/internet has helped here immensely. My refrigerator 'failed', and it just needed a new logic board. Way easier than building a computer. Risk was medium because it's hard to go too long without a refrigerator. I had a tankless hot-water heater fail, so replaced most of the parts inside. Eventually, figured out the exchanger had cracked which was about 1/2 the cost of a new heater. Lots of time wasted, though not much money. Bought a new one b/c the one was 10 years old. Risk was low because we could survive without hot water for a bit. I installed the new one with the help of a friend - saved about $3k. This cold caused an outside pipe to fail. I did PVC joins for the first time yesterday and they seem to be good. Cost was very little in both money and time. Risk is also low since it's outside. If what I did fails, I can always call a plumber. Furniture items I reuse all the time. It's amazing what a quick repaint and/or buying new upholstery can do. When I buy new furniture now, I try to only buy things with slip covers/easy to replace parts.