How long is long enough?

I come from long-lived genetic stock. My paternal grandfather and grandmother both lived well into their 90s, my mother into her 80s. I'm more familiar with my father's last years than with those of others but all were similar: they became dependent upon others after lifetimes of autonomy in which they had been the master of their fate, the captain of their soul as W E Henley put it in Invictus. This has been my mantra all my adult life, and could have been theirs too, especially my father's. Unlike his father, my father drank, smoked and womanized, which may be part of the reason he didn't quite make it to 90 years but died a few months short of that goal. It would be hard to find anyone more fiercely autonomous, more independent, more the master of his fate, the captain of his soul, than my father. All his life until soon after his 85th birthday no one else mattered: he was probably the most selfish man I ever knew. Then rather rapidly, everything changed. He went blind - macular and vascular degeneration did that to him, as it had to his father before him, and likely will to me too in time. He lost his sense of balance, and soon after that, he lost control of his bladder and bowels. What fate could be worse than this for someone so ego-centred! He was reduced to a state of dependency and infantilism requiring nurses to change his diaper, feed, wash and dress him in clean pyjamas. He had chosen to live his final two decades in Malta because of the generous tax laws. The people of Malta are more Catholic than the Pope, so he was lovingly cared for by nursing sisters of a devout and somewhat ascetic order and fed with plentiful quantities of plain and wholesome food that were the obverse of the gourmet meals he had conspicuously enjoyed in his previous life. I know that he lamented his fate, cursing - blaspheming - loudly and often when being moved about in his bed caused apparently excruciating pain in his arthritic spine and neck. He tried to die with dignity but he was acutely aware of the harsh reality that he was condemned to a long drawn-out death. I resemble him in many ways and among these is the high probability that my fate will be similar, despite differences in life style: I don't smoke, drink very moderately nowadays, and have never womanized. If anything these differences might prolong my life well into that period of dependency. Like my father I am an atheist, do not believe in an afterlife: when I die there will be oblivion only, so in this respect, being alive is preferable to being dead and expecting eternal paradise, or eternal damnation or some variation of these alternatives. Curiosity will keep me going if I lose my autonomy before I lose my life. I'm fond of saying that I want to live long enough to find out what my grand-children, and the children or grand-children of a few others among my close friends, do with their lives; and this quite simply is my main, maybe my only reason for desiring a longer time alive than the almost 85 years I've already had. This long period I've been granted, well over four score years, has been overwhelmingly enjoyable, at times almost transcendentally so. Looking forward, I can expect much that will be unpleasant, uncomfortable, perhaps painful. But that curiosity about what will become of the generation next but one after my own will keep me going after all other things that give me pleasure have been taken away. I live on the 11th floor of our condominium apartment building. I've often said that when life ceases to be enjoyable, I'll take a swallow dive off of our balcony. My curiosity will trump that action as far into my future as I can see. Maybe changing circumstances at some future time will alter my view of this, but I doubt it. I don't believe there is an afterlife so it's obviously desirable to make the most of the only life I will have.