For example, issuers will bump up the rate to 5 percent on summer gas purchases because it's peak driving season. Other issuers will reward travel purchases more during the winter holidays.
Sometimes you will need to enroll in these quarterly cash-back specials, so be on the lookout for special mailings or online alerts to register, Hronek says.
Another easy way to earn more rewards is to shop through the issuers' online shopping portals, says Dana Traci, vice president of rewards and product management at Discover. For example, Discover cardholders who shop through the Shop Discover portal, which features such retailers as Best Buy, Kohl's and the Apple Store, can earn up to 20 percent in cash back on their purchases. Other issuers offer similar bonuses.
"Online shopping portals give customers a clear way to maximize their rewards," Traci says.
Using your rewards card wisely
Even with the bells and whistles, keep in mind that a rewards credit card is still a credit card. That means sticking to the tried-and-true rule of paying off your entire balance every month.
People who keep revolving balances aren't getting the most out of their rewards and are usually paying a higher interest rate. Most issuers fund credit card rewards programs by charging higher interest rates on rewards cards, says Ulzheimer.
"If you keep a balance, you're really funding your own rewards program," he says. "Whatever you're earning in points, miles or cash back, you're likely giving it right back to the issuer in interest."
Another no-no is missing a payment, says Sherry. If you miss a payment, often you forfeit the rewards you have earned, she says. The same thing goes for long periods of inactivity on your card; you may lose the rewards or cash back you've earned.
Ulzheimer recommends cashing in (or redeeming) your rewards periodically instead of hoarding them. That way, you'll get the full value without the risk of losing them.
If you want to find out how much bang you're getting for your rewards, check out your year-end summary that issuers provide, says Pam Girardo, a Capital One spokeswoman.
"Simply divide the rewards you earned by how much you spent, and see what you come out with," she says. "That's one way for folks to see if they came out ahead."
If you don't like what you see, maybe it's time for a switch.