If we were to equate two parcels of land of equal measure, we could easily discern that although each one is equal to the other quantitatively, each one differs from the other in nature and character.
Every centimeter in the world is unique, and it is impossible to find even one speck of dust that is exactly equal to another.
The same is true of units of time.
To be sure, time can be measured in external units, and there would appear to be no difference between its various parts, between one minute and the next, between one hour and the one that follows.
But the truth is that each unit of time is distinct; every single moment is new and different.
Such an outlook engenders a serious attitude toward accounting for time and toward the utilization or waste of time.
Since every minute is unique, if it is wasted, that minute is no longer rectifiable; the time of rectification is already a different time.
–Rabbi Adin Steinsaltz