(Harvest) As 2017 enters its homestretch, we can’t help but marvel at the state of things: the U.S. stock market, the duration of its bull market, the magnitude of its gains, the incessant drumbeat of new all-time highs (over 50 record closes for the Dow Jones Industrial Average for 2017 as I write) and the absence of volatility (we set a record for the longest stretch without a 1% down day). Every investor, even those who eschew all forms of market timing, must now be asking the same question: “How much longer can this last?” For loss-averse investors, selling now probably feels like the right thing to do. And if we made our investment decisions on the basis of feelings, it would be much easier.