There are actually two apps to address this problem. For 99 cents on iTunes, the app from Impetus Technologies, for example, will notify you with both sound effects and vibration when your phone is charged so you can unplug it right away. Also provided by the app are data such as battery status and talk time remaining.

On the Android side, meanwhile, there's the like-minded and free . Either way, it's time to stop wasting all that energy and money just charging your phones.

8. MeterReadSimply monitoring your energy use can help you save between 10 percent and 20 percent on your electric bill, according to Zerogate, whose iPhone and iPad app is designed to help with just that. Priced at 99 cents, MeterRead gives you feedback on your energy use with each reading. Not only does it display the total kilowatt hours used since the last reading, but it will predictively calculate your total usage for the next 30 days.

9. Go Green

Though it takes a more generalized approach than many of the above apps, for Android offers a really nice guide to embracing green strategies, and many of them do pay off in savings as well. Priced at $2.99, it can pay for itself in a very short time through the savings you can achieve.