I carry a prepaid-service cell phone (Trac-Fone). The screen of the phone tells me how many prepaid minutes remain in my account, and how many remaining days I have within which those minutes must be used.

I pay attention to those times, and I find that my average actual use of the cell phone is one and a half minutes per day (a large portion being to my wife), which comes out to just about the days I have available.

Dave Oesterreich