The cashback rewards from the Citi Double Cash Card don’t expire as long as your account remains open and in good standing.  However, it will expire if you haven’t earned any cashback from purchases or payments for 12 months.  To avoid expiration, ensure that some transaction activity earns cashback at least once a year.  It’s always a good idea to take note of such details in your card agreement to ensure you’re making the most of your rewards. While at it, check out other cashback credit cards (up to 6% on groceries).