Parents are given 120 monthly calling minutes when they upgrade to Premium. These minutes expire at the end of the monthly subscription and renew each month the subscription is maintained. Unused monthly minutes do not carry over into the next month.
Parents on the Premium Plan have the option to purchase additional minutes (100, 300, and 1200 minutes options). Purchased minutes that are unused do not expire, even when your subscription expires. Parents must be on a Premium Plan to access their minutes.