Let's say Mike owes his cousin $50, but he really cannot pay her this year. So he calls her and offers to pay her with his gift cards worth $65, which were issued by his company. His cousin accepts the offer since she also regularly goes to the same establishments. Please confirm if his cousin's question is idiomatic:
Cousin: How long is each one valid for?
Mike: The first one (bookstore) is valid for one year, the second one (grocery store) for six months, and the last one (fast food) for three months.