Energy...

If you're anything like most cell-phone users, your phone is always on. It's always ready to take a call -- and always consuming power. And if your phone is anything like mine, that means it's probably also always in need of a recharge.

Now, it's great that cell phones are rechargeable -- could you imagine having to change the batteries every few days? -- but there's still a problem that makes them less green than they could be.

Your cell phone, you see, is a glutton. It doesn’t know when to stop sucking electricity from the wall. Oh, sure, the battery can only hold so much juice, but the charger keeps pulling power as long as it's plugged in. Your phone could fully charge in two hours, but if you leave it plugged in for four hours, you've used twice the amount of electricity that you needed to.

The best solution is to pay attention when you're recharging. Leave your phone out in the open and keep an eye out for that "charge complete" notice to flash across the screen. Then unplug it. (While it may be convenient, I'd recommend against letting a phone charge overnight. You won't be able to unplug it, and it could use hours worth of extra power.)

Need help remembering? Some phones (like these from Nokia) offer audible reminders to unplug a fully charged phone.

You could also switch to a solar charger (several are on the market), or even a wind-up charger. That's taking things even greener.

Even better, tech companies could get a move on and market more chargers that actually stop taking electricity when a device is fully charged. UK retailer Carphone Warehouse introduced such a device last year, but as far as I can tell, nothing like it is available in the U.S.

Until then, unplugging may be the environment's best friend.