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Dustin Waller hasn't paid for an airline ticket in over four years.
At 30, Waller and his wife, Kristin, optimize their credit cards to fly around the world for little to nothing. In fact, the couple currently has 35 credit cards open, which Waller manages and discusses on his website Waller's Wallet and YouTube channel.
"When my wife and I were getting married, we were looking at honeymoon options, and some of the airline tickets were so crazy expensive. I just thought there had to be a better way," Waller tells CNBC Select. "There's no way all these people are paying full price for these tickets."
Waller did a Google search to find cards and wound up applying and being approved for the Chase Sapphire Preferred® Card, which had a 40,000 point welcome bonus at the time.* He was able to redeem the points he earned for two round-trip tickets to Jamaica for $15.
It was this experience that led Waller to dive deeper into the world of credit card rewards. His original goal was to travel once or twice a year, but he's since been able to travel six to 10 times a year with all the points he earns.
Some of his favorite trips have included taking a helicopter tour of Hawaii, visiting the Blue Lagoon in Iceland, marveling at the views of the Swiss Alps, exploring the endless artwork at the Louvre in Paris and going to see Pompeii.
It's not easy for one person to manage 35 credit cards, but there are websites to help streamline the process. Waller prefers to track rewards on AwardWallet versus a spreadsheet.
AwardWallet tracks rewards for credit cards, hotel and airline loyalty programs and other memberships, such as Starbucks and Dunkin Donuts.
In addition to utilizing AwardWallet, Waller came up with a system to help Kristin know when to use a certain credit card. Waller uses a label maker to print out descriptions of what each card should be used for, such as dining, gas stations and everything else.
"She is very good at making sure she's using the right card at the right place to earn us the most rewards back, because it definitely does help us in booking all these trips," Waller says.
He also says the USAA Limitless™ Cashback Rewards Visa Signature® Card, while no longer available to new applicants, is one of his favorites for everyday purchases, offering a rare 2.5% cash back on all purchases and no annual fee.
The cash back Waller earns is deposited into a bank account that he designates as a travel fund. When he books trips, he'll use the balance in that fund to cover some or all of the expenses.
Since cash-back cards aren't known for big welcome bonuses, Waller opens rewards cards that offer point or miles bonuses. But he has to be mindful when opening these cards since many card issuers set limitations on how frequently you can receive welcome bonuses, often every 24 or 48 months.
For example, the application for the Chase Sapphire Preferred® Card says, "This product is available to you if you do not have any Sapphire card and have not received a new cardmember bonus for any Sapphire card in the past 48 months."
"The [card issuers] really tightened up over the last couple years," Waller says. "So I try to be more strategic and opportunistic on the bonuses when they arrive."
For him, this means cancelling cards or changing from one card to another card in order to be eligible for bonuses again.
While the average American has four credit cards, the Wallers once had 47 cards. In the past several years, he's decreased the number of cards they have to 35. But how does he decide when to close a card?
Initially, it depends on whether the card has an annual fee. If the card has no annual fee, Waller keeps it open since it helps with the average age of his credit history and his utilization rate. If there's an annual fee, things get a bit more complicated.
"If the card has an annual fee, I usually evaluate the card when the annual fee posts. When the fee outweighs the benefits, I will call for a retention offer to see if I can get more points or the annual fee waived again," Waller says.
If he doesn't receive a retention offer, Waller takes one of three actions: He cancels the card, changes the card to another one he wants, or pays the fee when the rewards benefits outweigh the cost. This can be a lot of work for the average cardholder, but for maximizers like Waller, it's all part of the fun.
"I like numbers," he says. "It's a puzzle, so being able to piece together that puzzle and figure out how you can travel to another destination in the world for a fraction of the cost is pretty awesome."
In addition to maximizing credit cards for personal gain, Waller helps family and friends benefit from credit card rewards. He recently flew his wife's aunt on her points to Hawaii for no out-of-pocket cost.
"Family and friends see the pay off in it, and they're starting to buy into it," Waller says. "It's really good to help people travel."
Learn more: How to make the most of your airline miles
Information about the U.S. Bank Cash+™ Visa Signature® Card, Discover it® Cash Back, Chase Freedom® and Uber Credit Card has been collected independently by CNBC and has not been reviewed or provided by the issuer of the cards prior to publication.
*The 40,000 point welcome bonus is no longer available. Please read our Chase Sapphire Preferred review for the current offer.