For me, it was using version control on my code. I was up late finishing a large programming assignment for class, when inexplicably at 3 am, my code stopped c

For me, it was using version control on my code. I was up late finishing a large programming assignment for class, when inexplicably at 3 am, my code stopped compiling with a super generic error message. Turns out I had somehow added a random character at the top line, but it took me the next 1-2 hours being dumbfounded, confused, over-tired and frustrated before I found the problem. It would have been a 60 second fix with a simple diff against the repo version. After that day, I learned how to use svn and always start every project (no matter how small) inside some type of version control system.