In January 2015, Kyle Zuvella and Andrea Cortina took off on an around-the-world trip. Their 10-month journey took them to more than 40 countries on five continents. They studied Spanish in Chile, explored Lord of the Rings landscapes on New Zealand’s North Island, swung by the Great Wall of China, and went on a South African safari before visiting the Middle East and more than a dozen European countries.

The remarkable part of their excursion: They funded most of their flights and two months’ worth of hotel stays with credit card rewards. After a year and a half of diligently racking up points and miles, they had stockpiled nearly 2 million points and miles between them.

Zuvella and Cortina, who are now engaged and live in Santa Monica, Calif., are part of a breed of credit card users—often called travel hackers—who milk the system by “churning,” or applying for cards on a regular basis, to take advantage of hefty sign-up bonuses. (To make the trip, Zuvella quit his job at Visa, where he made his first foray into the world of travel hacking. Cortina was in culinary school at the time.)

Zuvella, 27, was recently approved for his 61st credit card—although he uses only two to three cards regularly for everyday purchases, keeps a few more open to prop up his credit score, and has cancelled the rest. The majority of his miles came from sign-up bonuses. Cortina, 27, followed a similar strategy to bulk up her stash of points and miles, and the two of them used their rewards to pay for various legs of the journey in turn. “The highest return you can get from this hobby is just to target bonuses,” Zuvella says.

Even if you don’t share the couple’s gusto for cycling through sign-up bonuses or scouring online forums for redemption strategies, you can squeeze more value out of your plastic using some of their methods. (They blog about their trips and offer strategies at www.thefarawayguide.com.) Introducing a new rewards card or two and being more strategic about which cards you use can translate into free flights and hotel stays or hundreds of dollars in cash back each year. As long as you pay your bills on time and avoid carrying a balance, this strategy won’t hurt your credit score and may even boost it.

PICK YOUR CARDS

To decide whether a travel or cash-back rewards card works better for you, consider the findings of a 2016 study by personal finance site Nerd Wallet: Domestic travelers who shell out less than $8,600 a year on travel are better off using a cash back card and putting the money toward whatever they wish (including stateside trips). International travelers should focus on using a travel rewards card.

Experts recommend rotating your spending among two to three rewards cards. Once you have figured out which type of rewards suits you best, consider adding a more rewarding card to your wallet if you’re earning only one point or mile per dollar spent. Use the free tools at www.creditcards.com to kick start your research, or consult Kiplinger’s annual picks (see “The Best Rewards Credit Cards,” July). You can probably snag a sweet promotion to jump start your cache.