The credit history is reported on the cosigners credit reports and can be calculated into your debt ratio when you apply for a loan later. You could be denied if your debt ratio is high because of co signed loans that you really are not paying. It doesn't matter if you pay it or not, the liability is there for payment so it is included in your debt ratio. Your kids or brother may have the best intentions for paying the loan back but just know what you are putting at risk by signing that loan doc...