@Hammer1JDwatch
If your Nest Aware subscription expires, you will lose all your video history. (You can check your subscription here: https://store.google.com/subscriptions.)
If you go to your camera or doorbell in the Google Nest app or Google Home app and select "Delete video history", you will lose your video history for that camera or doorbell.
If you factory reset your camera or doorbell, you will use your video history for that camera or doorbell.
And of course, history rolls off when it is old enough (that is, after 10 days for 24/7 video history or after 30 or 60 days [depending on your subscription] for event video history).
