Lisa,
you know I really wouldn't worry about it too much. The thing is, if you look after it just right and do all the right things, it may last a while longer that's all. But if you just use it whenever the thing shows enough charge to do so, you'll be fine. These batteries are only about $50 ish so they are really good value for money, and if you have to replace it a year or so before the theoretical maximum life, well - so what.
Happy viewing
