Each year, consumers juggle a total of $100 billion in balances on gift cards Keeping track of these funds and making certain all funds are spent can require considerable time Increasingly, people are deciding that taking the time to keep tabs on their gift-card balances is a next-best alternative These individuals pay others to make sure they are spending all available funds For instance, a firm called Tango Card uses software to track gift-card balances and provide periodic reports to consumers The company also sends e-mails warning consumers when unused cards are about to expire before all funds have been spent. The fact that owners of Tango Card have a comparative advantage in keeping tabs on gift-card balances enables its customers to devote extra time to other activities, such as earning additional income
What is the comparative advantage of customers of Tango Cards who devote time to earning income instead of tracking their card balances?