I'm coming up on my second decade of building software, and I'm increasingly fed up with how I and we keep stepping on the same rakes. Like, a lesson someone on the team worked out, but the rest of us didn't pick up on in time. Sometimes I even forget my own prior learnings!

It can be big and small things. Months ago we worked out that anything mutating data has to be guarded at the event handler itself, not just the UI. Then a handler shipped whose only protection was a greyed-out button, the action fully reachable underneath. A genuine security hole, easy to miss for anyone who hadn't internalized the earlier rule, and invisible to whoever joined after. And yet the lesson existed, it just didn't reach the person writing the code until we happened to catch it in review.

Any of this resonate? How does it work for the rest of you who ship?

- After you finish a feature or project, where does what you learned actually go? Your head, a Jira comment, a doc nobody reopens, a retro?

- When you start something new, do you ever explicitly pull a past learning back in? Copy it, link it, reference it, or do you go from memory and hope?

- The one I most want to hear: the last time something you'd already figured out would have saved you real time, but you only remembered afterward. What happened?

I'm trying to work out whether this is a real shared pain or just mine. War stories very welcome.