Motorola

I have a T720 from Verizon that I have had for a couple years now. I haven't had a single problem up untill lately. I had an extended battery in and as of last week it seemed that it was loosing charge faster than normal. I don't use my phone too frequently, maybe 2 or 3 calls a day tops, and I would hold a full charge for about 3 days. Now It wont hold it for 1 day. I switched back to the original battery, and it's the same thing, actually a little worse since it's a smaller capacity battery. Is the phone just showing it's age or could it be something else?

Thanks