Every once in a while I get an opportunity to share my 4 reasons to leave a code comment:
1. An odd business requirement (share the origin story)
2. It took research (summarize with links)
3. Multiple options were considered (justify decision)
4. Question in a code review (answer in a comment)
Important caveat for number 4: if your code can be restructured in a way that answers the question without a comment, do that instead.
This originally comes from an article[1] I wrote in 2021 titled "Writing Maintainable Code is a Communication Skill".