You will hear many people saying:

When I am fifty I shall retire into leisure;

when I am sixty I shall give up public duties.

And what guarantee do you have of a longer life?

Who will allow your course to proceed as you arrange it?

Aren’t you ashamed to keep for yourself just the remnants of your life, and to devote to wisdom only that time which cannot be spent on any business?

How late it is to begin really to live just when life must end!

— Seneca, On the Shortness of Life