On the flip side, even as a "sophisticated" user, I can't tell how much bandwidth a given video will use, or how long I can afford to stream Pandora to my phone. But it doesn't mater. My carrier provides an app that I can use to check my usage, and I can see how much I've used as a percentage of my limit. It's easy to get a sense of "been watching a lot of video lately, gotta ease up on that," or, "oops, downloading that ISO over tethering wasn't a good idea." It's not long before you have an intuitive sense of what things cost, in terms of bandwidth. I find I don't have to pay much attention unless I use tethering, but my data plan has 6GB cap.