A:AnswerSteve: I suspect your plan is like mine which means your 60 minutes doubles to 120 every time you add time. The 90 days are simply added to the existing balance remaining on your phone when you purchase the additional time. As I understand it (I've never tried this just in case it's true) you should make sure you never let your daily time (i.e., number of days left on your phone) run out on your phone because you will also lose any remaining minutes.