We started with a 15 year mortgage and now have less than 5 years left. As our mortgage dwindles, there is less and less to deduct. I would rather save the extra that I would put on the principle in another vehicle, stocks, bonds, etc than reduce my mortgage at this point. Most of our payment, five years or less out is going to principle anyway. I actually tried to remortgage the balance for remaining five years and the rates never got low enough to even break even.