AAR: Access Request Approvals history - does it ever purge?

The seeded 'Access Request Security Administrator' role can approve access requests, but also create access requests (conceivably for themselves and approve them). Does the approval history ever purge? If not, then one could always reference back that a request was never made and approved by the same person. I realize a custom role could likely be used that removes the ability to create a request, but in general I would like to know the behavior of the AAR approval history. Thanks.