It all depends on how close to retirement you are.  If you are far from retirement...early 30's for example...then as long as the mortgage payment is not a stretch then it make no sense to pay down the house.  It all comes down to discipline.  Ideally, here is what most home owners should do.  It is not rocket science but it is amazing how many people tell me how smart this concept is.  I would have thought more people would have figured this one out. 

1) Find a house that you can afford a 30yr mortgage and either put 20% down on or pledge securities from your brokerage account to avoid PMI.

 2) Figure out the difference between a 30yr fixed and a 15 yr interest only that remains fixed for the full 30 yrs.  (they are out there and the rate will be slightly higher than the 30 yr fixed for the benefit of having the interest only)

3) each month take the difference between the two mortgages and put it into a good balanced portfolio (EX MALOX or OAKBX)  THIS HAS TO BE DONE OR THIS ENTIRE STRATEGY IS FOR NAUGHT)

4) get the maximum tax deduction but paying only interest

5) your monthly mutual fund investment outperforms the 6% mortgage rate over the length of the loan (max deduction PLUS  money working for you)

6) in yr 15 either refinance or take all of the money saved over the course of the 15yrs on a monthly basis and pay down equity helping avoid the baloon in mortgage payment.

DISCIPLINE DISCIPLINE DISCIPLINE