if you can't itemize paying off the mortgage might make sense because you are getting no tax benefit from the interest. However, you do not want to leave yourself house-rich but cash-poor, which means that if a "cash" emergency arose, you would have to borrow at a much higher rate. The general recommendation is to have 3 to 6 months of cash available to cover emergencies. Tax laws are now much more complicated, so it's a question of what the tax consequences would be if you had a spare $100,000. For some taxpayers, not paying off would be economically better, while for others, the reverse would be true.
