You can configure how many days that messages can remain in users' Inbox, personal, Trash, or Junk folders before they are automatically deleted. Mail aging is configured as COS attributes and can be overridden for individual accounts. The date is calculated from the day the message is received for incoming messages and the day the message was composed for sent messages.
The attributes are set from the Advanced Features tab for either COS or Accounts. You can set the number of days for
Email Message Lifetime. The number of days that a mail message can reside in any folder, except Trash and Junk folders, before being automatically purged. The default is to not delete mail.
Trash Message Lifetime. The number of days that a mail message will remain in the Trash folder before being automatically purged. The default is to purge mail from the Trash folder older than 30 days.
Junk Message Lifetime. The number of days that a mail message will remain in the spam folder before being automatically purged. The default is to purge junk mail older than 30 days.