For that $ 1 in mortgage interest and the benefit of the deduction you get back 25 cents.But if you had to pay taxes without that particular deduction , you would pay 25 cents in taxes but you get to keep 75 cents of your money ( because you won 't have a mortgage and interest to pay if you paid off your mortgage.Which is better to pay 25 cents or keep 75 cents ? Stop worrying about that tax deduction and get rid of the biggest expense in your budget -- your mortgage .