so i've been reading about the battery life optimization. now i'm wondering if the 10 hours that's possible for the phone is only under these condition. what if i keep my push email on all the time and data retrieval on all the time, how much will that affect the 10 hour reported time? i'm sure i'm not the only one that needs/wants data to be always on and push email to be always on so i'm wondering for those iphone4 users, how has that affected their battery life? thanks.