Not only does one's credit score affect their qualification, the fact of the matter also lies in the question, "Can I (the borrower) afford this mortgage?" In most cases the borrower can afford their mortgage. However, some borrowers seek to incorporate their unsecured debt into their mortgage (secured debt). They seek to pay off the debt that is outstanding in amount. These debts are called "liabilities", these liabilities are calculated into a ratio that lenders use to calculate risk. This ratio is called the "debt-to-income ratio" (DTI). If the borrower has excessive debt that he/she wishes to pay off, and that ratio from those debts exceeds a limit of DTI, then the borrower has to either pay off a few debts in a later time and pay off just the outstanding debt. When the borrower refinances his/her loan, they can pay off the remainder of the debt.