How are Retention Policies defined?

When the Archive service is first enabled, the administrator defines a default policy. At any time, that default policy can be amended, and/or additional policies can be created via the Management > Archive > Retention Policies section of the control panel. Administrators specify a name for a retention policy, set one or more criteria to define the conditions under which messages will be archived with that particular policy, and define the length of time (in months or years) that messages archived by that policy should be retained.

If there are multiple retention policies, administrators also determine the priority/ordering of each policy relative to other archive policies for the domain.