Cash back and rewards points earned in credit card programs like Chase Ultimate Rewards, Amex Membership Rewards and Citi ThankYou Rewards, don’t expire as long as you keep your card open. However, when you transfer those points to your airline frequent flier or hotel loyalty account, they become subject to the terms and conditions of those programs, and may expire if you don’t use them. Flexibility is one thing that makes credit card travel rewards points so valuable–they can be transferred to many different partners at will. As a rule, in order to retain that flexibility, you shouldn’t transfer any more points than you need to book a flight or stay.…