Definition
Cost of time is the principle that time is not a neutral backdrop in any contested endeavour but the primary cost variable. Sun Tzu develops the principle in Topic 2 of The Art of War with unusual quantitative precision: a 100,000-man campaign costs 1,000 gold ingots per day; long supply lines impoverish the heartland; prolonged engagements consume seventy percent of commoners' cash and sixty percent of the ruling house's wealth.
The principle generalises far beyond military campaigns. Every day a contested project drags on, costs compound — direct (cash, labour, supplies), indirect (morale, opportunity cost, focus), and strategic (the third party that pounces while you are tied up).
Why it matters
How it works
Cost of time operates through three accumulating mechanisms:
- Direct consumption. Every day in the field, resources are spent without producing the desired outcome — supplies depleted, wages paid, equipment worn.
- Indirect degradation. Soldiers' weapons dull; their training fades; the heartland that supplies the army empties of households as inflation depletes the farmers.
- Strategic exposure. "The local lords will be quick to pounce on any weaknesses." A prolonged engagement is an advertisement of vulnerability to every other actor in the system.
The remedy is speed combined with living off the enemy. The wise commander provisions once, moves decisively, captures supplies from the opponent (doubling the value of each unit captured), and finishes the engagement before any of the three time-mechanisms can do their full damage. "An expert good at deployment never needs a second troop call-up or a third round of requisitioning supplies."
The modern equivalent is brutal: a startup that runs an eighteen-month sales cycle against a single customer has often lost more in indirect costs (engineer attrition, opportunity cost, runway burn) than it would gain from closing the deal. The Topic 2 reading: set a time budget; if you cannot close inside it, withdraw and find a different target.