If you co-sign for a friends credit card and they fail to pay it will damage your credit history and lower your credit score.
When you co-sign for someone it will negatively affect your credit it they do not pay as they should. This is going to lower your credit score. With a lower credit score, it will be more difficult for you to get credit for things like buying a car or a house. When you do get a loan, the interest rate will be higher than what is charged for someone with good credit.
