You ask your laptop to do lots of things. But the harder a laptop works, the more juice it uses. There are plenty of times — that flight to Singapore, say — when it’s absolutely critical to conserve battery power. Here are three tips for maximizing battery life:

1. Disable programs and features

For example, enable your network interface card only when your laptop is connected to an AC adapter, says Dave Salvador, an IT network manager with a financial services company and an expert on batteries. If you’re trying to complete a task before you lose juice, forget multitasking. Keeping other programs or tasks running in the background drains battery life, Salvador says. Instead of relying on default settings, click on Control Panel and go to Power Options in Windows Vista to customize power-related features such as turning off the display and putting the computer to sleep.

2. Don’t use the DVD/CD-ROM drive

If you have important work to do on your laptop while on the go, refrain from using the DVD/CD-ROM drive. And if you want to know how much juice your laptop needs to power a movie, for example, Salvador suggests doing a trial run at home, measuring battery life. “To experiment, work on your laptop without using the drive, and time it. Now play a movie and work at the same time, and time it,” Salvador says.

3. Avoid extreme temperatures

The hotter a laptop runs, the more juice it consumes. Some cooling gizmos use fans — and drain power through a USB port. You’re better off with a low-tech solution. The itoPad ($14.97) and the Xpad ($24.95) are among products designed to keep your laptop — and your lap — cooler. Neither pad requires power.

Finally, says Salvador, add a solid-state drive (SSD) to your list of must-haves the next time you shop for a laptop. A laptop with an SSD runs more quietly and uses less power because the drive has no moving parts.

Levi Sumagaysay is a newspaper journalist, primarily in Silicon Valley. Sumagaysay specializes in business news, technology and electronic gadgets. Sumagaysay’s work has appeared in the San Jose Mercury News and other Bay Area publications.