One of the things which can go wrong with a co-signing arrangement is if one of the parties dies prematurely. While it is definitely an extra expense, it is wise to consider cheap term insurance - certainly on the primary borrower. Most of the time the primary borrower is younger and insurance is reasonably affordable. The reason you would do this is so that the mortgage gets paid in full if you die suddenly and there is no complicating mortgage left behind for your estate and co-signer to wrestle with.