This is a fun, friendly intro to spaced repetition. If you've spent a ton of time and effort learning something that's faded away in a few months/years - SR is how you maintain, and it's dead cheap: https://ncase.me/remember/
(But skip the shoebox and go straight to Anki.)
But the *real* value is now all this knowledge is available when you're making decisions and learning new things. You become smarter.
Octodon is a nice general purpose instance. more