What did Seneca mean by “On the Shortness of Life”?

Seneca opens his essay De Brevitate Vitae (On the Shortness of Life, c. 49 CE) by rejecting the complaint the title seems to promise. “It is not that we have a short time to live,” he writes, “but that we waste a lot of it... Life is long enough, and a sufficiently generous amount has been given to us for the highest achievements if it were all well invested.” The problem, in his account, isn't the length of a human life but how carelessly most people spend it: on busywork, on other people's demands, on ambitions that only postpone actually living until some future date that keeps receding. He is addressing Paulinus, a Roman official buried in administrative duties, and his target throughout is the person who is “preoccupied” (occupatus) — not idle, but so consumed by activity that they never step back to examine whether any of it matters. Seneca's sharpest image is of people who guard their money and property jealously but hand out their time, the one truly irreplaceable resource, to anyone who asks for it. He contrasts this with the philosopher's use of time: engaging with the great minds of the past turns a single lifetime into something like citizenship in every age, since Zeno, Chrysippus, and Socrates are as available to a reader now as they were to their own students. The essay's practical instruction isn't retreat from responsibility but reordering it — treating each day as if it might be the last available for the things that matter, so that when death does come, it arrives having interrupted a life well spent rather than one still being saved for later.