I recently reread Peter Drucker’s The Effective Executive. The entire book is gold and much of it is centered around the way we manage time. This is how he describes time:

"The supply of time is totally inelastic. No matter how high the demand, the supply will not go up. 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 no substitute for time. Everything requires time. It is the one 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."

Time is a pretty unique thing. I’ve recently started the habit of evaluating how I spend my time by looking back on my calendar every couple of months. When you’re going from meeting to meeting to meeting all day it’s really easy to think you’re spending your time wisely. I’ve found that I’m often not. And doing a frequent look back helps me change that.