With 25GB of inbox space for each user, managing space is rarely an issue. Company policies related to records retention, however, often create a need to enforce retention policies on email messages.
In Google Apps Premier Edition, you can not set a retention period for email. Once set, Gmail will automatically permanently delete all email messages older than the retention period.
If you want or need to limit user retention of emails, but need to retain corporate access to messages for legal or compliance reasons, we can add Google Message Discovery to your Google Apps service.
Google Message Discovery is an email archive/recovery/e-discovery service that offers secure, audited archives of all messages sent or delivered for up to 10 years. Message Discovery also works with most any in-house email system.