You need to create a retention policy to delete content after seven years from the following locations: - Exchange Online email - SharePoint Online sites - OneDrive accounts - Microsoft 365 Groups…

One policy is insufficient because Teams locations such as channel messages and chats cannot be combined with Exchange, SharePoint, or OneDrive locations in the same retention policy.

Microsoft Purview retention policies enforce a hard constraint that Teams locations cannot coexist with non-Teams locations in a single policy. Exchange Online, SharePoint Online, OneDrive, and Microsoft 365 Groups can all be covered by one policy, while Teams channel messages and Teams chats - which are compatible with each other - can share a second policy. This yields a minimum of two retention policies.

Three policies exceed the minimum because Teams channel messages and Teams chats can coexist in a single policy, eliminating the need for a third.

Four policies far exceeds the minimum - all non-Teams locations share one policy and both Teams locations share another, so only two are required.