The assumption behind every productivity system I have used is that time is the scarce resource. But that is plainly false, and everyone knows it from experience. An hour at seven in the morning with a clear head is not the same asset as an hour at four in the afternoon after four consecutive meetings. It’s energy, not time, that is the key factor.

Once you take the energy view seriously, several things follow. The first is that the highest-value scheduling decision is not how much you fit in but what you put in your best hours. If your sharpest thinking happens in the morning, then filling that window with status meetings and administrative traffic is not efficient use of time; it is spending your most valuable asset on your least valuable work. The second is that recovery stops looking like laziness and starts looking like maintenance. In training this is uncontroversial: nobody seriously believes you get stronger during the session rather than during the recovery afterwards. Somehow we have failed to carry the same understanding into cognitive work, where taking an afternoon off still feels faintly like cheating.

The third and most useful observation is that energy is not purely depleted by work; it is also created and destroyed by the kind of work. Some tasks leave me drained after twenty minutes, and others leave me more alive after three hours than when I started. That pattern is highly individual and mostly knowable, but only if you actually pay attention to it rather than assuming that effort and depletion are the same thing. Your job is to defend your calendar that will otherwise be filled by other people's priorities. So, as a reflection for today: when are you at your best, and what is currently occupying those hours?