Do I need to fully charge it before I turn it onand use it? Or can I fire that sucker up? Everytime I see a review/unboxing of an iPhone, Everyone powers it on right away. Does this decrease battery life? I've done some research on this, Some sites say yes, other sites say no. I know its an Li-on battery. But I don't know if it's better to charge it all the way, or let it die, then charge it. Edit: I know it's going to have some juice in it. I just want to Maximize battery life.