Ever forget to recharge your phone? Or find out that the recharger wasn’t plugged in when you left your phone hooked up to it overnight? Or simply use your phone a lot one day, and don’t have time to sit down next to an outlet for an hour or two? Those instances are when a phone power bank will save you. These are small and lightweight, so they’re easy to pop into a pocket or backpack, and don’t cost a lot. Remember, the need for a phone power bank isn’t just for convenience—it can also be for safety. If you’re traveling and run out of power (and especially if you’re overseas, where the power outlets are different from those in the U.S.), you want to make sure you’re able to stay in touch with fellow travelers, contact authorities if necessary, and reach out to emergency contacts at home.