This KB article explains what fields are evaluated when Archive and Purge rules run when determining whether a record is eligible for archiving or purging.
CA Service Desk Manager - all versions
Archive and Purge rules evaluate the following two fields when evaluating whether a record is eligible for archiving or purging:
Last Modified Date: Record will be archived only if the Last Modified Date precedes the Days Inactive on the Archive/Purge rule.
Active Flag: Only inactive records will be eligible for archiving or purging.