Checking refinance rates will not hurt your credit score, as long as you get all rate quotes within two weeks to a month of each other. The only way your credit score could be hurt is if your mortgage is your only credit-based loan. That could impact your “average age of accounts” (AAoA). However, AAoA is only 15 percent of your credit score. And most people have other credit lines outside their mortgage. So it’s not worth losing sleep over.