When should you need a new car battery?

A car battery has a limited lifetime, and that lifetime is shortened if you life in a part of the world that sees a serious winter where you use lights, heater, heavy cold starts, etc. I replace my batteries every 3 years before they start crapping out on me. 3 years seems to be about as much abuse as they can take in New England. If you suspect your battery is no longer capable of holding a charge, you can take it in to Pep Boys or Auto Zone and they will test it for you for free and either boost charge it for you or sell you a new one. Like I said, if your battery is 3 years old or more and the Pep Boy tells you it's shot, he probably ISN't scamming you into a new battery. And for 50-70 bucks, it's cheap insurance against a 150-dollar tow. after it stops working