Monday, Apple announced a recall of what they refer to as "a very small percentage of iPhone 5 devices." Apparently, some iPhones have suddenly begun to experience shortened battery life and may need to be charged more often. The affected phones are eligible for a free battery replacement.
The affected phones were sold between September 2012 and January 2013. Apple has determined a specific serial number range for the affected devices. They have also set up a handy serial number checker here which will tell you if your iPhone is eligible for a free battery replacement. You can find your phone's serial number in Settings by tapping General and then About.
