Commit to these simple habits and you could extend your notebook’s battery life by 25 percent or more!

Sleep Is Good
Use the operating system’s power-management features (in Windows XP, under Power Options in the control panel; or in Vista, under Mobile PC in the control panel) to set aggressive targets for when the display will go dark (say, after five minutes of inactivity) and when the machine will slip into sleep mode (no longer than ten minutes of inactivity). And if you can spare the extra time it takes for the machine to resume, set the PC to hibernate, not just sleep, when you close the lid.

Don’t Be Performance Hungry
Unless you’re running high-order mathematical calculations on that long plane ride, chances are you don’t need all the processing power your CPU is capable of giving. So in Vista, select the Power Saver power plan (found in the control panel, in the Power Options section) to extend battery life when on DC power, and leave the 3D gaming for when you’re near an AC outlet.

Dim the Lights
Turn down the brightness of the LCD panel (via the Function-key combo, or in the Control Panel’s Display Settings dialog) to the lowest level you can tolerate. The backlight sucks power like the Rockefeller Center Christmas tree.

Banish Non-Essential Components
When you aren’t actively using the Wi-Fi, Bluetooth, or IR radios, turn them off (via the hard switch, if your PC has it; or in the appropriate utility set), so they don’t trickle you dry trying to connect. Also, use USB-attached devices only when absolutely necessary. They aren’t getting their powers from positive ions in the air, you know.

Watch Scheduled Tasks
Be sure that your periodic virus scan is set to a time when you’re usually plugged in; running a full-disk virus check keeps the hard drive and CPU fully engaged for the better part of an hour.

Lay Off the Multimedia
A little in-flight music is nice while you construct that PowerPoint presentation, but streaming music from your hard drive (or playing a CD) means the disk (or disc) is always spinning.

Get More Juice
Let everyone else fight over that free AC outlet.
Designed to sit underneath your notebook, the APC Universal Notebook Battery 70 ($149; www.apcc.com) can provide up to six hours of endurance using its lithium polymer technology. It comes with a variety of notebook tips and features selectable output voltages. The unit adds 1.8 pounds to your carry-on, but it’s better than having your laptop run out of gas mid-flight.