Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

3-year horizon before trading up to next home: put windfall in savings, or pay off mortgage?
First, I would want cash around the time I made the move.  I would like enough for a 20% down payment, moving expenses, and enough for 6 months of mortgage payments on the existing house.  This way if the house does not sell quickly, you are safe.  As you approach the time it comes to move, you can work backwards on how much time you would need to accumulate that kind of money. Second, this does not have to be an all or nothing kind of thing.  Perhaps you use some of the proceeds to beef up your retirement, some to pay down the mortgage, and some for savings.  You could be very wrong about the market, even so it is a wonderful opportunity to add to your nest egg at such a young age.  My own self prefers to do things in ratios.  In your case I might do 10% of the proceeds in for retirement, 10% for savings, and 80% for mortgage reduction.  (You may want to also add some charitable giving.)   I really like paying down the mortgage.  Not only is it a risk less investment, it reduces your personal risk.