Mophie
1.) Poor battery life. 2.) Not enough storage for all your photos, movies, and music.
Mophie, a company best known for making charging accessories for mobile devices, has a fix for both with the Mophie Space Pack. The Space Pack is a case for the iPhone 5 and 5S that provides extra battery life and additional storage for all your stuff.
Like other Mophie cases, the Space Pack has an internal battery that you can switch on to charge up your iPhone. You can also use it to charge your phone with a standard USB cable, which is much more common than Apple's proprietary Lightning charger for iPhones and iPads. Mophie says the new case can provide an additional full battery charge. That should be more than enough to get you through a day of heavy usage.
As a bonus, the Space Pack comes with 16 GB or 32 GB of internal storage for keeping extra content that normally won't fit on your phone. Mophie also made its own free iPhone app called Space for managing that content.
The Mophie Space Pack isn't cheap though. The 16 GB version costs $149.95 and the 32 GB version costs $179.95. That's almost the cost as a 16 GB iPhone 5S. If you think it's worth it, you can pre-order a Space Pack here. It ships in March.