It really depends on what you're doing. If you're just browsing the web, checking e-mails, etc you're unlikely to get to that cap unless that's all you do. Streaming is where you can eat into that cap quickly. IIRC correctly, streaming music uses about 1MB per minute. Video uses about 350-400 MB per hour. So if you devoted your data to exclusively streaming music, you could listen to about 42 hours of music. If you devoted it exclusively to streaming video, you could stream about 6 hours of music. I'm under estimating to be safe.