The three big points I gleaned from this letter are:
1. a Stoic (cosmopolitan) never retires from the universe
2. hide your retirement (from the daily grind) in plain sight
3. in the pursuit of wisdom, it's better late than never
The Cosmopolitan's Work Never Stops
While a Stoic may decide to retire from employment, he ought to have learned he never retires from the Cosmos. He still yet has work to accomplish.
when we have assigned to our wise man that field of public life which is worthy of him, – in other words, the universe, – he is then not apart from public life, even if he withdraws; nay, perhaps he has abandoned only one little corner thereof and has passed over into greater and wider regions; and when he has been set in the heavens, he understands how lowly was the place in which he sat when he mounted the curule chair or the judgment-seat. Lay this to heart, – that the wise man is never more active in affairs than when things divine as well as things human have come within his ken.
In his retirement from employment, he has work on his soul yet to accomplish. He may spend time reflecting on wisdom and perhaps he may observe that he can share this wisdom with those who still have years of life left on this rock floating in the Cosmos. When the retired Stoic begins to see the divine as well as daily human affairs, perhaps he can share counsel for his fellow-travelers who will cross the path he treads today.
Retirement from Employment Ought to be Hidden in Plain Sight
Making a show of your retirement from employment may attract attention. The flash of expensive cars and big homes may indicate the wealth you have amassed over a lifetime of work, but to satisfy the ego may welcome prying eyes and thieves. Therefore, Seneca advocates us to not "vaunt one's retirement" but that we also ought not to "[withdraw] from the sight of men" as this also is a form of vaunting. To vaunt also means to advertise and "to advertise one's retirement is to collect a crowd."
Therefore, retire from your employment, but do it in plain sight. Perhaps, find a home that suits your needs rather than your ego. Drive a car that gets you to where you need to go, but no need to be flamboyant. I can't help but think of Sam Walton driving the same truck from 1979 to 1992, even after earning millions of dollars.
Retirement from Employment, but not from Work
And even after you retire from employment, you still have work to do.
When you withdraw from the world your business is to talk with yourself, not to have men talk about you. But what shall you talk about? Do just what people are fond of doing when they talk about their neighbours, – speak ill of yourself when by yourself; then you will become accustomed both to speak and to hear the truth. Above all, however, ponder that which you come to feel is your greatest weakness.
When the lionshare of our day is no longer spent in work meetings, then we will have time to hone in on our weakness, in order to correct them. If others were to spot our weaknesses, what would they say? This is how we ought to approach finding our weaknesses when we have much more time on our hands.
What, then, am I myself doing with my leisure? I am trying to cure my own sores ... I do recommend retirement to you, but only that you may use it for greater and more beautiful activities than those which you have resigned.
But what is the point of self-improvement at such a late stage of life?
Let us do what men are wont to do when they are late in setting forth, and wish to make up for lost time by increasing their speed – let us ply the spur ... I shall depart a better man.
If you are convinced there is a path to wisdom, then get yourself going on the path. Never deviate from the path once you are convinced. And if you've not achieved the attainment of wisdom before you retire from your active life, then use your new-found time to pursue this noble quest. You will have departed this life "a better man."
None of us know what awaits us after death. Perhaps we have lived and will thousands of times as part of the Eternal Recurrence or perhaps we regress or progress into another life based on Buddhist reincarnation. Or, maybe this is the only life we will live and there is nothing before or after it. Regardless of your perspective, I think there is a case to be made that we should never give up our quest for wisdom and improving ourselves. Our allotted time is sufficient; we simply need enough urgency to get going and to keep pursuing.