Gates:But, yeah, Bro's point is spot-on in terms of loss of liquidity. I would say it's very clear that in this case you would want to save that money in a taxable brokerage account on the side, and invest that money for this future goal. If you pay down your mortgage, that's locked up. Who's to say that another financial crisis happens and the value of your home goes down and then you're upside down. Actually, I guess he wouldn't be upside down at that point, because he'd be paid off. But the loss of the value of your house.