My FICO is now 841, and I haven't really tried to get-it-up. Paying off debt is not hurting your son's credit score. He'll need credit history, and for that he needs credit cards that he uses very little (ratio of "used" credit to available credit). Ideally, he uses his card only once or twice at the gas station, and then pays it off. That will, in time give him a rising credit rating. Unlike Dave Ramsey, I do not believe in "no credit rating" stories. By the time all of his credit history has been completely erased, he can have substantial equity in his home. I'd aim for 760 or more, and my wife, who never used credit cards before me and once had a car loan, has now an 811 FICO, without even trying. Time and discipline will do the work for him.