Irvinecommuter said:
			
		
	
	
		
		
			If you keep your mortgage, you get the tax deduction and have the lender holding the carrying costs.  Meanwhile you can invest in a mixed portfolio that is likely to yield above 5%.  Of course there is risk but just about every investment has risk.
		
		
	 
I'm purposely playing the devil's advocate here.
Using cash to pay off debt is the most risk-free investment you can make. I recently read a happiness study that said paying off your mortgage was one of the things that makes families significantly happier.
If you borrow at 3.5% and get 5% from your investments, you are taking a lot of risk for not a lot of return. And always remember - don't subtract the tax deduction on your mortgage interest unless you also subtract the tax owed on your investment.
Here's another question: If you were a financial advisor and you had clients in the following situations, would you give them the same advice?
Client #1: I am one year away from paying off my 15yr mortgage and I'm 40 years old. 
TI: Borrow 80% against your home and invest it in stocks!
Client #2: I bought a house for cash last year.
TI: Borrow 80% against your home and invest it in stocks!
Client #3: I am 55% LTV.
TI: Borrow 80% against your home and invest it in stocks!
Client #4: I inherited a home debt-free.
TI: Borrow 80% against your home and invest it in stocks!