Bought the iPhone 5 a couple of days ago, really happy with it so far. However, it's my first ever smartphone let alone iPhone so I'm a bit of an amateur in some respects. I'd like to keep my battery running as long as I can. With that in mind do I need bluetooth on at all times? I haven't actively used it to do something such as transfer files, but I'm wondering if bluetooth has a bigger importance that I'm not aware of.