Damn near 100% of the time for a few reasons...
1. It became a habit while driving a pickup for about 10 years where you basically have to back in.
2. It is safer and easier when you are leaving.
3. It is easier to get my wheels alllll the way to the edge of the curb in end spots.
4. I have a camera on the back but not on the front. I only had to hit the front lip on a curb once to learn that lesson
