Historically my wife and I carry over data, a couple times we went over the limit so I bumped us up to the next size plan, that seemed to be more than enough. Then we went over again, so I would purchase an extra gig here or there and eventually going up to another plan. What I don't understand is my wife's phone spends 99% of it's time connected to the home wifi. But yet this week it says she's used 6GB of data, mostly on social media, which she does not even use. She doesn't even have a social media account. This last time I paid our bill and I noticed it said we had 75% of our data left, two days later we were out of data. Why? We haven't done anything different, updates are set for over wifi only.