Success story: Sabrina Karl

Highway sign with the words Rewards-Next Exit

Sabrina Karl knows how to take control of a credit card and use it to her advantage.

For the last five years, Sabrina, 36, and her husband have charged as many household and personal expenses as possible on their United Mileage Plus Platinum credit card to earn rewards in the form of airline miles.

The credit card, offered by Chase, gives one mile on United Airlines for each $1 spent on purchases as well as special bonuses.

"We charge every single thing we can on this one card," she says. Groceries, eating out, local and long distance phone services, along with charitable donations, internet service, gas -- even the water softener bill -- are all charged on the card, the only credit card she has.

"I never have more than $20 in my wallet at a time because I so rarely use cash," notes Sabrina. "In fact, I use my credit card for so many things that I often go a week or two with just five or six bucks in my wallet."

The miles they've earned have allowed Sabrina and her husband to fly free from their home in Madison, Wisc., to vacations in New Mexico and the Canadian Rockies, and they're planning a trip to either Central America or the Caribbean later this year.

When her grandmother passed away last fall, Sabrina booked her younger brother a ticket to Calgary using miles from her stash so he could attend the funeral.

With such short notice given the circumstances, the airfare would have been almost $800, which my brother would have found almost impossible to afford," she explains.

Sabrina investigated various rewards cards before choosing the United Mileage Plus card and has since considered switching to a card that gives miles useable on any airline. However, she opted to maintain status quo.

United offers a plethora of flights from her airport, she's been satisfied with the card's terms and she can pay the $60 annual fee with miles, "essentially making the card completely free."

She offers these tips for how to make the most of your rewards card:

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