Some numbers, like your age, you can pretend don't matter. But three digits you shouldn't take lightly are your credit score.

New research from Credit Karma, an online consumer finance platform, found that bad credit -- a score of less than 640 -- could cost you up to $230,000 more in interest over a lifetime than someone with excellent credit, a score of more than 750.

"Poor credit has far-reaching implications these days -- impacting your insurance rates, ability to get a job, promotion, an apartment, and results in you getting higher interest rates on a mortgage or car loan," says Leslie Tayne, an attorney in Melville specializing in financial issues. "You'll pay more for many necessities."

Despite late-night TV ads, there is no quick fix when it comes to credit.

Check your credit report: You can get a free report at an nualcreditreport.com. "Look for negative information on it, like missed or late payments, and make a list of what you have to do. Also check for false information. Maybe there's a case of fraud that's ruining your score," says Howard Dvorkin, chairman of Debt.com.

Do the right thing: Establish a history of paying bills on time. "Pay them when they arrive, or take advantage of automatic online payment services," suggests Greg Lull, head of consumer insights for Credit Karma in San Francisco.

Another important factor in your credit score is how much of your available credit you're using. "You want this to be very close to zero, and no greater than 30 percent," says Lull.

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Set up and follow a strict budget that allows you to free up cash to pay down debt aggressively.