Our forum is for a university society, we get lots of students joining every year, who sign up for the forum.
The things discussed can be (very slightly) sensitive, and so we want to restrict access to those people who are actually involved. People who haven’t been involved for more than a year likely aren’t coming back, so we want to remove their access.
I guess it’s kinda similar to this use case in this thread, but not quite as strictly defined: