The summary.
TEAM FILES LIVE IN SHAREPOINT
Which is where permissions, retention and storage are actually governed. Understanding that explains behaviour that otherwise appears unexplained.
Files shared in chat are stored in the sender's personal storage and leave with them — share in channels for anything that matters.
ASSIGN PERMISSIONS TO GROUPS, AND AVOID BREAKING INHERITANCE
Separate content needing different access into different sites instead. Broken inheritance makes it impossible to establish who can see what.
And permissions alone do not tell you who can reach content — sharing links grant access outside them.
RESTRICT WHO MAY CREATE SITES AND TEAMS
Uncontrolled creation produces hundreds of inactive containers within months, and content becomes unfindable.
Require more than one owner — a team whose only owner leaves cannot be administered.
PREFER METADATA TO FOLDERS
Folders permit one classification; metadata permits several.
FLATTEN STRUCTURE BEFORE MIGRATING
Deep paths exceed limits and those files fail to migrate or synchronise. And never recreate the old structure exactly — it carries forward every problem it had.
