So after pondering this thread, I wrote a check yesterday for $ 60K to pay off the house. I had been thinking about it for a while, and decided there was no time like the present. I bought the house for $ 465K in the summer of 2015, and have been making substantial payments on the principal at irregular intervals. It is now worth about $ 600K or so.
Especially given the nature of the local healthcare market, and my job, I decided it was a good idea to pay it off while I still had a job, so come what may, we would have a roof over our heads. I had always planned to pay it off before retirement so this just accelerated the process a bit. I had the money in the bank earning crap interest, as opposed to paying 4% interest on the mortgage.
This will be the second house I have paid off, in my history of owning four houses in the inflated Seattle market.