Contrary to popular belief (or at least the beliefs of AP staff), Google doesn't actually automatically empty its Drive trash items. Soon, it will; Google has just announced that Drive will delete all trash items after 30 days, starting in mid-October.

Starting October 13th, Drive will automatically delete any file that is put in the trash after it's been there for 30 days. Shared files already used this behavior, but this will now apply for all Drive items. For files that have already been there, likely for years in many accounts' cases, the deletion will occur 30 days after October 13th. G Suite admins, however, will still be able to restore items deleted from the trash up to 25 days later for active users.

The rollout will begin October 13th, though it could take more than 15 days to reach everyone. Users will be notified in Drive starting September 29th.