The notifications are automatic and based on a period of inactivity. As soon as the system notices activity in the team, the counter starts over.

The expiry is set to 45 days of inactivity.

A notice will be issued at 30 days, 15 days, and 1 day before the Team expires.

The following user actions will lead to automatic renewal of groups

SharePoint – View, Edit, Download, Move, Share, Upload Files
Teams – Any comment in the teams channel

After a Team expires, there is a 30 day grace period to recover the chat history and related files. 30 days later the files and history is deleted permanently and unrecoverable.

Check Expiry

To see when your team is set to expire :

Launch Microsoft Teams.
Select the Teams icon.
Choose Manage Team from the menu.
Select Settings.
You'll see Team expiration at the bottom of the page, and a renew button if the team is inactive.

Browser not supported