Yesterday I puzzled over: I have found many studies, conducted by businesses, universities, industry associations and the military, that support the basic notion that, for most people, eight hours a day, five days per week, is the best sustainable long-term balance point between output and exhaustion. Throughout the 30s, 40s, and 50s, these studies were apparently conducted by the hundreds. … Somehow, Silicon Valley didn’t get the memo. … Five-day weeks of eight-hour days maximize long-term output in every industry that has been studied over the past century. (