I don't have a car, but my parents have their own cars, and whenever we go out together as a family, we usually take my moms car if it is a long trip, or a party, because her car is newer and looks nicer. Most of the other times, we take my dads car.
But! We are a family of five, so if we ever have anyone over, we only have five seats in the car, so we HAVE to take both cars.
They both drive each others car frequently, it's just labelled as my mother's and father's car, because he gifted her the car.