My wife an I both have the iphone 4s. My monthly data usage is around 400 mb however my wifes phone is a 2 GB each month. She is a lite user all around so there must be a setting that is causing it.
Only thing I can think of is that she uses a sport app that tracks her excercies walks - I know that often drains the battery but would it increase data usage?
Any other ideas?
Ken