Another reason to pay off your mortgage early

On last Friday's Dave Ramsey show there was a couple who paid off their house the at age of 37.  Dave said if they invest the $2,000 a month they would have put into paying their mortgage into mutual funds for 30 years (they'd be age 67), they could make $6.9 million. And he also mentioned putting money that would go to a car payment over the course of 40 years would let you have over $5 million.  Of course this is if you can get a 12% return, which we all know doesn't happen all the time. But even so, this is yet another reason I want to pay this mortgage down and hopefully some day be completely done with it!