The Ultimate Guide to Solving iOS Battery Drain

(Yes, that is a linked post to a linked post to a post. Deal with it.)

Marco Arment:

The low-reception-areas tip is especially good. […] Last time I flew cross-country, the two passengers next to me both left their iPhones in fully-on normal mode. I put mine in airplane mode. All three of us used our phones periodically during the flight. When we landed, their batteries were both nearly dead (which they loudly complained about for 20 minutes) and mine was still over 70% charged.

Here in Sweden (but it happens back home too) I get excellent cell coverage in the city but subpar in the rural area. Turning off the cell reception really helps me get through the day. And with iOS 7, plane mode is really quick to switch on.