What does it mean when it says that my "balance expires..."?

Question

This is my first cell phone. It's from Virgin Mobile and it was prepaid with $15. By "balance expires", I think it means that the remaining of that $15 will be removed. If I'm correct, why would they remove MONEY? If I put more in my phone, will the remaining of the $15 be there?

Answer 1

Typically, the minutes expire after a certain amount of time.  If you purchase additional time before expiration, the minutes do not expire.