I never wondered how much of my "unlimited" iPhone data plan I was using until AT&T introduced their tiered plans a year or so ago. When I at that time checked

I never wondered how much of my "unlimited" iPhone data plan I was using until AT&T introduced their tiered plans a year or so ago. When I at that time checked my usage history I was a little surprised to see that I was rarely using more than 200MB per month, so I actually dropped down to their $15/month plan and ended up saving some money.