Letting points expire
If you like to hoard your cash-back rewards for a big redemption someday in the future, you may want to reconsider your strategy. Those rewards may expire, depending on your card's fine print, and the point of having a cash-back card becomes moot.
Nineteen of the cash-back rewards credit cards in Bankrate's survey, or nearly a third, come with an expiration period on rewards. That period ranges from three to five years, depending on the card.
To avoid losing free cash, Ulzheimer recommends making cash-back rewards redemption an annual event. For example, cash in right before the holidays to help with the shopping load. Or, give yourself a birthday present each year with your cash-back rewards.
"You don't want to let your cash-back balance get so obnoxiously high that if you do forget and your rewards expire," he says, "then you'll really kick yourself."