How often do you put anti-freeze in car?

Answer 1

You should only have to check the level during your regular oil change. If it is a little low, it's probably just the water evaporating off of the antifreeze in an unpressurized reservoir. If the tank is pressurized, (radiator cap on the tank) it should, in theory, not lose any coolant between services. If the coolant regularly goes down to the add marks on the reservoir, you have a leak somewhere, most likely.