>Many times I've gone back to code I'd written previously, it seemed overly complicated, I replaced it with a simpler version... that failed... that reminded me that was what I'd tried originally and then replaced it with the more complicated version for a good reason.

>So now I have a new rule: every time I try a simple approach and it fails and I replace it with a more complicated one that works, I add a comment explaining the previous strategy and why it didn't work.

My strategy is to comment out the failed attempt and leave it there for next time.