power outlet, you're going to want to do everything you can to make sure your battery doesn't die out prematurely. You'll want to start out with the more obvious tips: disable anything you don't need, turn off anything that emits light that isn't your display, dim your display to the lowest usable brightness, and block Flash or any other CPU-intensive apps that may start running without your expressed permission. Generally you can eke out a lot of extra battery life with these tips, but you need to make sure you don't have any CPU vampires running around on your computer. They'll suck the battery dry and you may not realize until it's too late. Apps like Dropbox , RescueTime , or anything that regularly requires CPU cycles can add up quickly and cut your battery life down more than a negligible amount. A few other lesser-known tips can also help your laptop maintain a charge a bit longer. Disk access is a battery killer, so you can avoid excessive disk read and write times by defragmenting your disk regularly. You can also help avoid more frequent disk access by adding more RAM to your machine. You're not going to want to do this on an airplane, but if you travel a lot and have been considering a RAM upgrade anyway you now have another minor reason to actually do it. Although disk access can drain the battery, it's better than accessing files from a CD/DVD or external USB device. If