My N7000, after a year of using it , recently lasting not long. charged it up to full 7am then it had dropped to 60% at midday. It normaly lasts 2 days. The phone is on contract but think it was out of warranty
babara, on the N7000 see if you can find (Application Manager) what apps are always running on the background. Some game and social apps are real battery drainers. If you find anything running which you don't need, just stop them. Application manger will also inform you of the mb each app has downloaded, lets say for the last month. The larger the number of mb which is displayed you'll know which app is running most of the time. And you can question if you need it to run. And set your screen brighness to Auto. It helps too.
Could be the battery.I just fixing my battery life issue by swapping a new out of mpj last week. Could also probably an app you have installed, which can run in the background like Facebook. You can try a factory reset before picking up a new battery