7th
Effective people know that time is the limiting factor. The output limits of any process are set by the scarcest resource. In this process we call “accomplishment,” that resource is time. Time is also a unique resource.
One cannot rent, hire, buy, or otherwise obtain more time. The supply of time is totally inelastic. No matter how high the demand, the supply will not increase. There is no price for it and no marginal utility curve for it. Moreover, time is totally perishable and cannot be stored. Yesterday’s time is gone forever and will never come back. Time is, therefore, always in exceedingly short supply.
Time is totally irreplaceable. Within limits we can substitute one resource for another, copper for aluminum, for instance. We can substitute capital for human labor. We can use more knowledge or more brawn. But there is not a substitute for time.
Everything requires time. It is the only truly universal condition. All work takes place in time and uses up time. Yet most people take for granted this unique, irreplaceable, and necessary resource. Nothing else, perhaps, distinguishes effective executives as much as their tender loving care of time.

