When asked how long they want to live, people often say no more than ten years above their country’s average lifespan. This, mind you, is in a world where aging is still inevitable; people know that they won’t be in top shape during those ten extra years, and yet, perhaps hoping that they might be an exception to that rule, they still wish for that little extra time. Even when told that they will live these extra years in complete health, the most common choice is the current maximum recorded human lifespan, which is roughly 120 years.

If we assume that no rejuvenation therapies are available to extend the time you spend in youthful health, then it is somewhat understandable if you don’t feel up for a very long life, because the odds are that its final decades will be increasingly miserable; however, if rejuvenation therapies were available, and you could be fully healthy for an indefinite time, why stop at 120 years? Life extension advocates have probably all had their fair share of conversations with people who insist that 80-odd years will be more than enough for them, health or no health—worse still, some don’t care about preserving their health precisely because they think that 80 years is a sufficiently long time to live.

How long one wants to live is only his or her business; just like no one should have the right to force other people to live no longer than the current maximum (an imposition that would indirectly result from a hypothetical ban on life extension therapies), no one should have the right to force anyone else to live longer than 80 years, if that’s what he or she wishes for whatever reason. Indeed, it’s not the right to die when you see fit that’s at issue here; the question is whether people who claim that 80 years are enough have seriously thought the matter through before making their minds up or are simply parroting what others typically say out of social pressure.

No assumption comes without consequences

For the sake of argument, let’s assume that, even in an ideal world where comprehensive rejuvenation keeps everyone fully healthy and young-looking, 80-something years are indeed “enough”; this assumption has consequences, of course, which may be useful to examine in detail if one is to make up his or her mind as to whether the assumption holds water in his or her specific case.







The first, obvious observation to be made is that, by the very definition of “enough”, the assumption means that you don’t need more than about 80 years of life. Naturally, one doesn’t “need” years for their own sake; what one may need is time to accomplish objectives that one cares for or to do things that one enjoys doing. Thus, saying that 80 years are enough means that such objectives and things can be all be brought to completion and ticked off your list within 80 years—or, for some reason, you won’t care to accomplish quite everything on the list or keep doing things that you like after you turn 80. It also means ruling out the possibility that you might develop new interests or add new objectives or things not included in the original list—or, again, that if it does happen, you won’t really care much for some reason.

This is not impossible. There’s no reason to think that no one, ever, might come to the conclusion that he or she has gotten enough of everything without necessarily being fed up with everything. The question is, unless you’ve already reached that point, are you confident in your prediction that you will certainly reach it when you’re in your 80s—or any other specific age? It would be unwise to make such absolute assumptions about your far-future self, and even more unwise, on the grounds of these assumptions, to not take action to give yourself the option of living well past 80; what if, once you hit age 85, you realize that your list has grown far longer than you’d anticipated, but you’ve already got one foot in the grave because neither you nor enough other people have bothered to endorse rejuvenation decades before?

The most sensible thing to do would be to wait until you actually do reach the point of no return, if that ever happens, and then decide whether terminating your life really is the best option; don’t burn your bridge before you get there. Meanwhile, it might be worth having a close look at the practical consequences of the assumption that 80 years, while still in the prime of health in a world in which rejuvenation is common, are enough.

You’re not set in stone

Even assuming that you can achieve all “traditional” goals of a human life to your satisfaction within 80 years, you need to take into account the very concrete possibility that, as you tick off existing goals, new ones will present themselves. Similarly, as you satiate your interest for a certain hobby, passion, or career over the years, others are bound to form. You’re bound to change, and if you think that you won’t change much, the odds are that you’ll be proven wrong.







In a paper titled “The End of History Illusion”—freely downloadable here—social scientists describe the homonymous phenomenon by which people of all ages underestimate the extent to which they will change in the future, compared to their present selves, despite reporting having changed significantly in the past. In other words, people always say that they’re very different from their younger selves, but they don’t really think that their future selves will be much different than their present selves—regardless of their present age.

According to the study, the magnitude of the illusion does shrink somewhat with age—older people change less significantly than younger ones, so their prediction comes closer to the mark—but we must take into account that this was a study ran on normally aging people, whose health and brain plasticity, and therefore options, diminished as they aged. We don’t know what the results of a similar study run on rejuvenated elderly people would be, but there’s little reason to believe that a biologically young person with the mental agility of a 25-year-old would be set in his or her ways forever simply because his or her chronological age is past 80. This may well happen if someone hasn’t really learned much over the course of his or her life, but accumulating knowledge is bound to have the opposite effect—the more that you know, the more that you will take pleasure in knowing and will want to know, and the more that your interests are bound to flourish.

Assuming that you will never develop new passions or hobbies past what you might develop over the course of 80 years simply isn’t a sound assumption. Similarly, it isn’t safe to assume that something in which you lost interest years ago won’t ever become interesting again.

Would you get tired of…?

If you think 80 years of life are enough, you’re assuming that 80 years of anything are enough; it is important that you think about each and every one of these things individually and try to find an answer. There is no absolute answer; it depends on who asks the question. Thus, while the following questions might sound like they are asked rhetorically, keep in mind that they are not.







Again, on the assumption of full, everlasting youthful health for yourself and the rest of the world, would you get tired of being in the company of people whom you like and love? (Mind that this is different from falling out of love with someone or not liking people you used to like anymore—which may well happen at any age, incidentally implying that, despite age, either you or they have changed; this means becoming unable to enjoy the company of anyone at all, forever.) Will you have visited everywhere there is to visit in just 80 years, or will you have got enough of traveling altogether by then? Will you have read enough books, watched enough movies, or gone through your favorites enough times that you won’t wish to see them ever again? Will you be fed up with your favorite food and with food in general? Will you no longer enjoy a night out with friends or practicing a sport? Will you no longer enjoy a sunny day or cuddling up in a blanket with a good book and a warm drink while a storm is raging outside? Will arts and music of all genres and sorts have utterly and hopelessly lost their appeal? Will you no longer enjoy sex, love, humor, or laughing? Will you no longer be awestruck by the Milky Way in a starry sky?

These are only some of the things to consider when deciding whether 80, or however many, years of them will surely be enough; you can easily come up with other things that apply in your specific case. Furthermore, don’t just consider whether 80 years of what exists and you’re aware of right now are enough; consider whether you wouldn’t mind a few decades of things that you’ve yet to discover or that don’t yet exist. In a sort of variant of the end-of-history illusion, people tend to assume that our world and our species won’t be very different in the future, despite the absolutely obvious fact that they have changed a lot during the course of history—our world in particular would be barely recognizable for people who lived one or two centuries ago, and we really can’t say that there’s no difference between the world now and even 30 years ago. Are you ready to literally bet your life on the idea that, after you’ll have hit a certain age, whatever that may be, the world will have reached the form that it will always be in and will no longer stimulate your interest? Will you bet your life on the idea that the future will always be nothing but more of the present?

There’s no absolutely right answer, but whatever your personal answer may be, it would be in your best interest to figure it out before you decide how long you wish your life to last.