Does it really matter?

His median score is 489, hers is 512. They finally have extra money at the end of the month because she's returned to work. I think they should save and invest because it will help them buy a home. They got advise from her inlaws telling them to slowly make small payments on their medical bills on their credit report because that's what will help them. So which one matters? Saving the money or wasting it making small payments on medical bills?