I tried it out. Was previously on the 15GB plan with 4 lines. It's a requirement that all 4 lines be smartphones. My elderly in-laws are on our plan and had a flip phone. Upgraded them to an iPhone. Was one that I had stashed away in a drawer - new, but hadn't been used (I won't get into how that happened). My reason for switching to the unlimited was that I decided I was going to start streaming music over my phone in the car instead of paying for satellite radio. I *thought* that would use up a lot more data. After being on unlimited for about 2 months there was a definite increase in data use from doing the streaming - but it was nowhere near what I thought it would be. My other half and I only went up to using slightly more than 3GB per line with the streaming. The in-laws use almost zero data, and my mom uses almost zero data (she was already on an iPhone). I switched us back to the 15GB plan since there was nowhere near the data use that I was expecting, and the unlimited was costing about $20/month more. Plus the in-laws with an iPhone was a total disaster (they can't figure out how to use it) - so they're getting their flip phone back.