I've noticed a poor battery life on my iPhone since I bought it but it's starting to get a little frustrating. I charged my iPhone last night and took it to work today with a full charge. It's been in my pocket most of the day, having only sent a few texts and taken two pictures (with flash) however returning home I find 20% left. I let the phone drain to 11% after which it jumped up to 18% (all by itself) and it's done this several times now. I've also found it switches itself off on 15% occasionally; a clean reset hasn't resolved the issue. More of a frustration than a cause for concern. Has anyone else noticed similar issues?