It’s easier than trying to remember it all. I have a habit of doing this at work, and it benefits not only me but the next person who needs information. It helps justify promotions and raises too.

When you can do this openly it helps build a public body of work that can earn you better jobs.

The overhead is really slim. I'm basically using issue comments as personal notes - the time consuming part is figuring out what to do, while turning that into a sentence of text and maybe a link or pasted example is a fraction of that effort. And the productivity boost I get from having useful notes is enormous.

It's particularly valuable for multi-tasking: I can have a lot more projects on the go at once if I don't have to remember details of what I was working on or where I had got to for each one.