Been reading this.
Mailbox Purge - Zimbra :: Wiki
Now I just need to ask the experts something to make sure, before I go ahead.
"When a mailbox is purged, all attributes are considered. In cases where there's both a system and user-level policy is specified for the same folder, the shorter interval is used"
Does this mean, if I set a system retention policy of 90 days and the user sets E-mail message lifetime: to 0 days (never purge) that the user's mail will never be purged?
So in effect the user can override the system policy?