I track every repair I do in a spreadsheet. Date, part, time spent, what went wrong. Hit 1000 entries this morning. Scrolled back and realized I've been replacing power supplies preemptively on a specific desktop model for no reason. The logs showed zero of them actually failed. I just assumed they would. That's a lot of wasted money over 3 years. Anyone else ever catch themselves doing preventive work that the data says is pointless?
Same here man. My spreadsheet has saved me from myself like a hundred times. It's basically a very boring diary of all the dumb things I've done with a soldering iron.