At a young age, have strict rules. Example: they can watch stuff on a phone/tablet only at the doctors or at an airport (or on a plane.) That works for us. Let

At a young age, have strict rules. Example: they can watch stuff on a phone/tablet only at the doctors or at an airport (or on a plane.) That works for us. Let them watch something in the car only ONCE, and they'll be sure to remind you that "watching in the car is ok."