You can fully recharge lithium-ion batteries, such as the one inside the iPod, 300 to 450 times before they give up the ghost. When that ghost is gone, you need a new battery. For $99, Apple will ...
Update: Despite recent misrepresentations, Apple does offer a $99 iPod battery replacement program at this point in time and there are also 3rd party options available for only $50. According to ...