I think you missed his point (which could certainly have been made better). How I read it was more like this: If you are told/know that you will be working 14 h

I think you missed his point (which could certainly have been made better). How I read it was more like this: If you are told/know that you will be working 14 hours today because everybody is in crunch mode, then taking ten minutes every hour to get coffee and relax isn't a big deal, and another ten minutes on HN every hour isn't a big deal, and another ten minutes on email every hour also isn't a bid deal, and now you've spent only 7 hours actually working for 14 hours at the office. On the other hand, if you are told you can only work 9-5, then you will save all the HN time for later, and you will probably ignore some of the less important emails, so that's an extra 15 minutes per hour of actual work, so you worked 6 hours in your 8 hours at the office. Source: I interned on a military base that had exactly this rule. It really focuses you to know you have x hours, no more, each day.