LPT: You know that unmarked bag, box, or container you think you'll remember the contents of, months or years out? You won't. Label *everything.*

This is a life Pro tip that has served me extremely well. If you decant something into an unmarked container, put a box away for storage, or collect something in a ziplock bag that you think will be marked by some indelible experience that you're absolutely sure you won't forget or lose track of: guess what? Odds are you're going to come across that thing at some point in the future and wonder when it was from, what it contains, all so you can figure out what to do with it.

To avoid this future confusion: grab a marker or pen and clearly label whatever it is, on the box or container or with a little paper slipped inside. Future you will thank you.

EDIT: it's been fun to see this blow up. There are a ton of other great tips in the comments - be sure to upvote and elevate your favorites.