If you ever want to use your dash cam in a rental car, then static film is a great way to attach the dash cam to the windshield without having to struggle to remove it when you turn the car in. I discuss the static film that worked for me in this post: https://thomasdash.com/does-static-film-work-for-dash-cams/

If you’ve never owned a dash cam, then you may not know that a dash cam can be configured to record while your car is parked. I discuss some of the things you need to do to enable it in this blog post: https://thomasdash.com/can-a-dash-cam-record-while-parked/