Seneca-Letter I, On Saving Time
Continue to act thus, my dear Lucilius – set yourself free for your own sake; gather and save your time, which till lately has been forced from you, or filched away, or has merely slipped from your hands. 
The man who does not realize the true nature of time will forever be bound and enslaved. Thus, Seneca tells his friend to free himself. There is but one way that his friend can be free. He must gather and save time for his own sake. Until a man recognizes that time can be stolen, wasted, or simply allowed to move on without a man’s notice he is not truly free. He will be bound by those who take his time without even the slightest regard for how quickly a man’s time has passed. Therefore, time is the greatest and most precious of commodities, it does not belong to another but is univocally yours and yours alone. Do not allow anyone to use your time for their own selfish gain or for a trivial pursuit.
The most disgraceful kind of loss, however, is that due to carelessness. 
How many men whittle away the moments of their lives carelessly assuming that the sands of the hour glass will somehow return to the upper bulb? Those moments no longer belong to life but are in the hands of death. True freedom resides in understanding that the hours that one spends are debits to one’s allotment of time. These moments are finite and yet men allow them to pass with ease, at times numb to the apperception of the loss that has occurred. To use time in such a way is carelessness and is a disgrace to the sentient being.
Lay hold of to-day’s task, and you will not need to depend so much upon to-morrow’s. While we are postponing, life speeds by. Nothing, Lucilius, is ours, except time. 
A man must be about his business, today. Most men have heard the expression, carpe diem, seize the day. Seneca, reminds his friend prior to this passage that it is equally important to seize the hour, carpe horam . Procrastination has no place in a man’s life as he is borrowing from what he neither owns nor possesses. Holding on to a day, presupposes that one must hold onto the hour, which in turn means that man must hold onto the moment. Allowing time to slip by in idleness belies the value of time. Modern man with his time saving devices, has been lulled to sleep by his gadgetry. Those “time-saving” devices do not save a moment if those free moments are wasted.
What fools these mortals be! They allow the cheapest and most useless things, which can easily be replaced, to be charged in the reckoning, after they have acquired them; 
How many men have allowed their earthly possessions to enslave them? Man becomes indebted to the baubles and trinkets of life. He is a made a fool in considering such worthless goods as the pièce de ré·sis·tance of his life. These same men never look back on the most precious gift they are given, that of time. There was a scene in the movie The Village where the William Hurt’s character says something akin to this “We are grateful for the time we are given”. The only way to show true gratitude for our time is to seize the moment and not allow time to be stolen from us. We must use this great commodity while fully realizing that this loan can never be repaid.
For, as our ancestors believed, it is too late to spare when you reach the dregs of the cask. Of that which remains at the bottom, the amount is slight, and the quality is vile. 
Seneca ends with practical advice. The man that has squandered his life cannot begin to save time when he has come to its end. Certainly, no man can know when his life will come to an end, but an old man who has wasted his time will be in no position to begin this process. Once life is nearing its end, the best days are long since forgotten. What is left at the end often lacks both quality and quantity.
Seneca; Holland, Francis Caldwell (2016-02-19). Seneca Six Pack – On the Happy Life, Letters from a Stoic Vol I, Medea, On Leisure, The Daughters of Troy and The Stoic (Illustrated) (Six Pack Classics Book 4) (Kindle Locations 653-654). . Kindle Edition.