Most car batteries are rated to last about five years. A battery may last shorter or longer, depending on the way you drive, the weather and other factors. For example, extreme cold or heat can shorten a battery's life. Taking a lot of short trips is hard on batteries, too, because the alternator doesn't get a chance to fully recharge them in less than about 20 minutes of driving.
If your battery is 3 to 5 years old, it's probably a good idea to have it tested so you don't end up stuck in a parking garage some dark night. Bring it on in to any of our stores, and we'll check it for you, free.