Not all the recipients of the time-sweepers' largesse are people. About forty miles outside Timbuktu, a medieval mosque, buried in sand, receives a delivery every decade or so. Somewhere below the floor in the Aegean sea, a Trojan galley is miraculously preserved in mud. Similarly, the time-sweepers gift a little extra time to a temple in Mexico, and preserve a haul of dark-age treasure in a Galway bog.
A certain amount of charitable time is kept back for emergency situations, both small and large. It is parachuted in in times of desperation, and has facilitated peace deals, changed battles, and allowed numerous fathers to make it to the delivery room in time.
The time-sweepers are, by their very nature, a tidy and orderly sort of people. They wish that humans would think more about throwing away this valuable commodity, but don't expect it'll happen any time soon.
There isn't a moral to this story. It's just that if you are planning on throwing away your time, please remember - somebody has to pick it up.