This setting determines how long someone who has had their membership expire should remain until they are permanently erased from the system. By default, members who expire are never
purged, their memberships just remain inactive. You can specify any number of days (from 1 day to 1 year) before they are erased.
This setting only applies if an expiration date is set on memberships, so that memberships expire after a certain number of days. Otherwise, membership never expire. See Expire.