how does CQ5.5 housekeep all the audit log and workflow instance by default?

As seen in the question, how does CQ5.5 housekeep all the audit log and workflow instance by default.  Our user is having a situation that the audit log and workflow instance are growing  rapidly and become very large overtime.

Also, can the audit log and workflow instance history export to CSV/PDF before they were remove from CQ?

Thanks