I have had an iPhone on AT&T since launch. I never went over a gig in any month. I have used half a gig in 2 days with Verizon!! Worse, it uses LTE while I am at home with a rock solid wifi connection. If I turn cellular off altogether I can still see, for example, a YouTube video. But if I leave it on, while still connected with wifi, it sucks data like a vampire. W t f???? And, all day, it leaks data even with no apps running! H e l p !!