I disagree. Tiny libraries can be fine indefinitely. For example this little library which inverts a promise in JavaScript.
I haven’t touched this in years and it still works fine. I could come in and update the version of the dependencies but I don’t need to, and that’s a good thing.
I think total number of commits is probably a good metric too. If the project only has 7 commits to begin with then it's unlikely to get any more updates after it's "done". But a 10 year old project with 1000 commits where the last commit was 3 years ago is a little more worrying.
I haven’t touched this in years and it still works fine. I could come in and update the version of the dependencies but I don’t need to, and that’s a good thing.
https://github.com/josephg/resolvable