systemd-tmpfiles-clean will watch directories and periodically purge old contents.
eg
d /var/cache/man 0755 man man 1w
will delete files older than a week from /var/cache/man
Is there a way to apply max lifetimes to files matching a pattern? I can't find any way to tell it to, say, remove *.txt files older than a month from /tmp/foo.
-- Frank Van Damme
Make everything as simple as possible, but not simpler. - Albert Einstein