I don't have a car, so I do all my errands on the bike.
Days that I don't have any errands, I'll ride a 3/4" mile "rectangular loop" around my neighborhood, to reduce the "regression" from not riding. 4 easy right turns and I'm back where I started at my driveway. I'll do it 1-6 times, depending on the mood. After participating in this forum, the 1 loop days are pretty rare.