Schedule cognitively demanding work during your measured…
Schedule cognitively demanding work during your measured peak attention window and batch shallow work outside it to maximize output quality per unit of effort invested.
Why This Is a Principle
This derives from Directed Attention as Depletable Resource (finite executive function resource that depletes), Ultradian and Circadian Cognitive Rhythms (ultradian and circadian cycles create predictable capacity variation), Conscious Processing Is Metabolically Expensive (deliberation is metabolically expensive), and Attention is a finite cognitive resource that must… (attention must be allocated). It's actionable (schedule hard work at peak times), general (applies across all knowledge work), and prescriptive (tells you how to structure your day based on biological constraints).
Source Lessons
Attention is a finite resource
You wake each day with a limited reservoir of focused attention — roughly three to four hours of genuine deep work — that depletes with every act of sustained concentration and cannot be refilled by willpower alone.
Externalize your energy and mood
Tracking your energy and mood on paper reveals patterns invisible from inside the experience — because you cannot optimize a signal you never measured.