A good quality battery should last four or more years. Battery failure doesn't usually occur spontaneously. Most often there are telltale signs that your battery is going bad. If your engine cranks too slowly or the battery requires frequent recharging, these may be indications of a failing battery. Many starting problems are often misdiagnosed as a battery problem when they're really caused by another part. If the battery is less than four years old, be sure to have your mechanic test it to make sure that's where the problem lies. Corrosion that's collected on the battery's terminals may be the cause of a starting problem. This corrosion can be cleaned off with a wire brush or a mixture of baking soda and water. Never smoke or allow an open flame near your battery. It contains explosive gases that could ignite. Contact a local auto mechanic or auto parts store for more information on your car battery.