If you want to conserve battery power, the easiest way to do so is to turn wireless off. To do so, click the Menu button and select the Wireless Off option. The Kindle uses more power when it is using Wireless features such as checking for blog updates and accessing the internet. If you turn off your wireless and use it only as needed, your Kindle’s charge will last much longer. This is also useful for when you are traveling by plane.
Advanced Tip: The Kindle doesn’t need to be charged to full every day. Its charge will last a long time especially with wireless turned off or used only as needed. There are a few topics on the Amazon forums where they talk about the Kindle’s battery life in detail.