The batteries in these macbook pros have a much longer life than previous batteries, but they are not "user replaceable." In other words, they will be expensive to swap out. Please follow these instructions to maximize the life of your battery. This will dramatically enhance the life of your battery.
● Please do not leave your laptop plugged in all the time. The battery needs some
exercise. Every now and then it would be good to run your battery into the “red” and
then charge it up again.
● To extend the time that your computer will run on battery you may want to adjust different energy settings such as:
○ Brightness. Dim your screen to the lowest comfortable level to achieve maximum battery life.
○ Bluetooth. Unless you are using bluetooth, be sure that it is turned off. Just check the toolbar at the top of your screen.
○ Applications and Peripherals. Disconnect peripherals and quit applications not in use. Eject CD's and DVDs if not currently accessing them.
● You also extend the life of your battery if you will shutdown rather than sleep your computer at night.
● These new batteries are designed to hold their life for up to 1000 charge cycles. As a point of reference, the older macbooks would hold theirs for about 300.
● They also should run for a longer time on the battery. Some users have reported up to 7 hours.
http://www.apple.com/batteries/notebooks.html