Inspect the real account
Retention varies with product, subscription, settings, administrator actions and legal holds. Check the oldest visible record and test a small authorized export. A recent migration can make a long-running business look like a short-lived dataset.
Distinguish visibility from exportability
A search result, backup or archived account may not be available in the same export route. Attachments, threads, custom fields and deleted-user records may need different permissions or methods. Capture those differences in your inventory.
Do not alter retention casually
Changing retention or restoring old backups can introduce security, contractual and legal issues. Coordinate with your administrator and counsel. A potential data deal is not a reason to ignore a deletion obligation or legal hold.
Record evidence
Keep the system, plan, inspected date, oldest exportable record, method, permissions and known gaps. Recheck immediately before delivery. Vendor documentation describes the product; your settings and records determine your actual history.