Credit card

Photo: George Doyle/Valueline/Thinstock

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They Don't Send Up Red Flags
You probably know that making late payments on your credit card or having an account sent to collections is bad for your credit score, which means you'll get a higher rate on any loan you might apply for, which means less money for you over time. (Here's one example of how a poor credit score can cost you at least $7,500 more in interest on your mortgage over five years.) However, there are some less obvious things that can trigger a "hard inquiry" into your credit (that's when a financial institution checks your credit report— a type of inquiry that can lower your score). These include renting a car using a debit card and charging too much on your business credit card.