String literal. A string literal or anonymous string is a type of literal in programming for the representation of a string value within the source code of a computer program.
As usual, the devil is in the details. For instance, with some prepaid wireless plans, your minutes are only good for a limited time, usually 30 to 90 days. If you don't use them before they expire, they are simply subtracted from your account anyway.
Most prepaid SIM cards have expiration dates. If the SIM card is inactive for a certain period, usually about three months, users will lose whatever money they have put on the card and haven't yet used. After about nine months to one year, many operators will deactivate the SIM card and phone number.