Just that writing clever code, however defined, doesn't expend much of a cleverness resource - if anything, it strengthens it. Walking strengthens the legs and

Just that writing clever code, however defined, doesn't expend much of a cleverness resource - if anything, it strengthens it. Walking strengthens the legs and increases endurance. However, no Roman Legionnaire would command his men, as if more marching would only increase capability, and they could therefore march forever and as much as they want. Instead, it's best to reserve the fast marches for when a goal is attainable which gives a tactical or strategic advantage. There's only 24 hours a day to be clever, and there's only a limited number of hours per day a given person can muster the concentration to be clever. That is, looking at each piece of clever code in isolation. Which only applies to an isolated problem, as in a coding interview. In a programming project or a startup, it's more like a military campaign, where there will be many, many interrelated problems over many years.