Email messages are a very common source for security problems, so keeping an adequate record can be very helpful when investigating an incident.

Follow these steps to set the default retention rules for all email messages:

1. Click on the Mail tab.
2. Enable Set a default retention rule for Mail.
3. Set the Duration to one of the following options:
   • Indefinitely: This will keep the messages for as long as the account exists. I recommend using this option.
   • N days from when the message was sent: This will keep the messages for the amount of days set here. You can specify a period of up to 36500 days (100 years). If you set a limit, then you must also set the Action after expiration, as follows:
     • Expunge deleted messages: This will erase the messages that the user has already deleted
     • Expunge all messages: This will erase all messages that are older than the retention period
4. Click Save.
5. If you set a retention limit, you will be asked to confirm that you understand the consequences. Please read and confirm each.

Now that we have set the retention rules for email messages, let's set up retention rules for Drive in the next section.