“you observe a typical Monday–Friday work or school schedule, then Friday, and particularly Friday afternoon, has four main upsides over some other leading planning-time contenders (Monday mornings or Sunday nights, judging by my surveys). There’s little opportunity cost. It is hard to start anything new on Friday afternoons. Many of us are sliding toward the weekend at that point. If this time would otherwise be wasted counting the hours until it is acceptable to sign off, why not repurpose it for planning? You can make Monday productive. If you plan on Fridays, you can make full use of your Monday mornings. Many of us have more energy at the start of things than we do later on. Planning on Fridays allows you to use that Monday-morning energy”