Energy Management
The principle that sustainable high performance depends on managing energy, not just time.
High-leverage activities are often draining. If you only optimize for time (maximizing hours on high-leverage tasks), you deplete the energy needed to do them well. The fix: include energy-restoring activities in your schedule — not despite their lower direct leverage, but because they fuel the high-leverage work.
Applied by Greg Brockman at Stripe: coding wasn't always the highest-leverage use of his time as CTO, but it recharged him. Returning to it gave him better organizational perspective, better ability to support people, and more capacity for the draining high-leverage stuff.
A corollary: the activities that restore energy are often the same ones that give you ground-level feedback about what's actually happening. Brockman's return to coding restored both his energy and his feedback loop simultaneously — they were the same thing.
Related to ooda-loop-for-projects: maintaining an OODA loop also requires energy; you can't run a fast loop while depleted.