My Cygolite Hotshot (tail light) is two or three years old, and the battery no longer holds a charge. I contacted the company from their web page, and a person named Paul from the company said I could return it for battery replacement. I'm willing to pay, but he hasn't yet told me if I have to or how much it will be. So far, so good. This is the normal lifespan of a LiIon battery, so I'm not complaining.