Originally posted by another user
if you’re using your iPhone 5 in places a with a very strong (4- to 5-bar) LTE or 3G signal, your cellular battery life may approach that number, but if not, the cellular antenna will struggle to maintain a signal, and fall well short. Because LTE and 3G/4G towers are in a state of build-out flux right now, our tests suggest that many LTE users won’t come close to Apple’s promised numbers.