When you move your Google My Drive files to Trash, they remain there indefinitely or until you delete them forever.
Starting Oct. 13, Google will change its retention policy for My Drive Trash items and will automatically deleted those items after 30 days. Files that have been in Trash for longer than 30 days also will be automatically deleted after Oct. 13.
Google is changing its retention policy for My Drive Trash to be consistent with Shared Drives and Gmail. Trashed files can still be restored before the 30-day period ends. All trash items will be retained in the Google Vault retention system. Do not depend on Trash as a means of archival or view Google Vault as an end-user backup solution. You are expected to manage your files appropriately.
Google will display a warning banner in Drive and other G Suite apps prior to implementing the new policy.