If your iPhone 5's battery just doesn't have the kick that it feels like it should, you might be able to get a new one for free. Apple has found that an apparently small batch of iPhone 5s (not the S or C) that "may suddenly experience shorter battery life or need to be charged more frequently." You can check if yours is included by entering its serial on Apple's website, and get a replacement if it is.
If you are one of the (un)lucky few, you just need to back up your data, wipe it, and visit your local Apple Store or Apple-approved retailer for a fresh new battery. One major catch: If you've got a busted screen or other damage, you have to fix that first, on your own. But if that's not a problem, the program has already started in the US and China, with other countries to follow on August 29th. So go and check your serial number here. Best of luck, and here's to hoping your battery never dies. [Apple via 9to5Mac]
FYI if you are planning to do this, call the Apple Store ahead to see if they have batteries and if not, if you can order one and make an appointment for the replacement when it comes in. I just went to my local Apple Store only to find out the entire city is out of batteries (I guess it isn't THAT small a number of phones that have this issue). They ordered a replacement kit for me and I'll have to go back when it comes in.