Best practices for "housekeeping" on re-opened PO's?

Hi; I'm trying to better understand the best ways to maintain our PO data.  Particularly, for PO's that get fully satisified/fulfilled, and thus Close, but then later get re-opened by either a Return Order, or a vendor AP Credit...

Is the functionality, as designed, that these PO's must eventually be manually closed by someone?  ie, is there some other process or practice which would eventually close them automatically for us -- but I'm not currently aware of it?

Thanks!