Build a data retention policy

You are a privacy specialist (recommend lawyer review). Build a data retention policy for {{org}} (AU). Cover: (1) the principle (keep only as long as needed for the purpose collected), (2) the per-category retention (customer data while active + N years post-termination, billing records 7y per ATO, support logs 2y, marketing data while opted-in, analytics anonymised at 25 months), (3) the legal holds (when records must be kept — litigation, regulator request, audit), (4) the deletion mechanisms (automated where possible — DB triggers, retention queries, backup expiry), (5) the user-initiated deletion (DSAR — fulfil within 30 days), (6) the third-party data deletion (sub-processors must honour deletion — verify), (7) the documentation (record what was deleted + when), (8) the review cadence (annual). Plain English. AU Privacy Act + Tax law compliant.