How are deleted items handled in Office 365?

When you delete an item from your mailbox in Office 365, it is moved to the Deleted Items folder. Items in that folder stay there for 1 year (365 days) from the date of deletion. You will see this folder in your list of folders and may move items out of it as needed.
After 1 year, or if you delete them from the Deleted Items folder, they are moved to the Recoverable Items folder. The Recoverable Items folder will be invisible you, but mail items can be recovered by your area’s e-mail administrator by request. Items in this folder remain for 30 days before permanent deletion.
Once a mail item then leaves the Recoverable Items folder, it is completely gone and cannot be recovered.