Let me caution you that, of course, no one knows what will happen next week, much less in 2035. If we add the uncertainty of estimating four centuries worth of progress, clearly we are in the land of make-believe. But make-believe can be fun (and instructive too)! Let's take a look.
If longevity were to improve by half a percent a year for 400 years, someone with a life expectancy now of 75 years could live to be over 250! While some scientists cite 180 years as the outside limit on the potential life span, who knows what might be learned in the future? Perhaps people will grow their own new stem cells for cloned body parts that will be replaced every 50 to 75 years.
Let's assume a low-ball case. Life expectancy for 60-year-olds grew by about 10 percent in the United States during the time from 1900 to 2000. If that trend were to continue for another four centuries, 60-year-olds would have average life expectancies of 120 years of age! Sixty would become the new forty.
Many people will see the possibility of being aged and infirm for the bulk of one's much longer life. But that's probably not what will happen. Huge advances are being made in replacing the parts of our bodies that wear out the fastest, like knees, hips, and spinal discs.
Organ replacements are becoming increasingly common. We also know a lot more about rehabilitation after an injury or disease. Increasingly, those who replace body parts will find themselves functioning better than before rather than less well. With weight and exercise training, some 90-year-olds now report being more agile and active than when they were 50.
As for marriage, perhaps people who realize that a life commitment to a spouse could be for more than 100 years will make the effort to learn better how to build and nurture their relationships. Appreciating that those years when children will dominate a marriage will be relatively few over the length of the marriage may also improve both spouses' interest in having a great relationship with one another.
In addition, average family sizes keep getting smaller. Perhaps tomorrow's norm will be to have one child rather than two. That would certainly provide much more room for spouses to have primary relationships with one another.
People who have many marriages following divorces often try to disguise that fact. Imagine what it would be like to have had fifteen failed marriages over a much longer life. Perhaps the unattractiveness of going through so many unpleasant endings to relationships will encourage more interest in better marriages.
Families are an area where that 120 year life span will make the most difference. If marriage and child-bearing occur at young ages, someone who has 30 descendants at 80 could have 62 descendants at age 100 . . . and 126 at 120! Even those who marry and give birth at more advanced ages could have 62 descendants at 120. This size in the descendant population may also influence marriage length.
Many parents hang on until the youngest child is grown before separating or divorcing. Realizing how many family events you will be attending with your former spouse, you may find that it's a good idea to stay together at least until the great grandchildren are grown.
Clearly, the generative possibilities of old age are greatly changed if you now have dozens of youngsters to keep track of, mentor, and cherish. The oldest generation will have a much greater role in creating a sense of family among far-flung sets of hundreds of relatives (when you consider cousins, great aunts, and great great uncles). Can you imagine having such a family reunion?
You also won't have to lose your parents at such a young age. Where many people now suffer those losses in their 50s or 60s, your parents will probably be with you into your 80s or 90s, even if they die somewhat prematurely.
Friendship will also take on new meaning when that kid next door can become someone you'll know for 115 years. If you make one good new friend a year for life, you can have so many good friends that it would take you weeks just to have couple-on-couple dinners with each one.
Homes may have to become a lot bigger to accommodate parties for friends and visits by the great great grandkids. Here's what home ownership progression might look like: You live in a small place when first married. You move to a bigger place with a yard in a good school district at the time when you have your one or two kids.
After 25 years, you move into a small place again. After 10 to 15 years more, you buy a bigger place than you've owned before where the kids and grandkids can come visit and fun together. Then, in another 25 to 30 years, you need to buy another place that's twice as large!
If your working life can extend for 80 to 100 years, it's also a good time to think differently about both careers and education. Not only will your knowledge become obsolete every 6 years or so if you don't work at it, but your incentive to stay in the same field will diminish. It won't be much more work than keeping up with your field to go learn some other business, profession, or line of work.
Longer lives will also mean that guarding against accidents, injuries, and violent crime will be more important to people. Manufacturers, service providers, and governments will probably have to vie for providing the safest environments and assistance. Homes will come equipped with gear to make major accidents all but impossible.
With so many more years to gain the benefits of compounding the value of a person's investments, we can expect that it will be easier than ever to accumulate substantial wealth. Buy one piece of property on a lake somewhere, and in an increasingly crowded world you can sit back and enjoy the thought that they aren't building much more lakefront property any more. Safe bets like spots overlooking Central Park in Manhattan and Waikiki beach views from up the mountain in Honolulu will probably create many trillionaires in the future.
You can now buy index funds of several thousand of the largest companies in the world. These stocks compound in value around 5 percent a year in real terms. That means doubling in purchasing power every 15 years. Put $100,000 into such an index fund at age 30, and the value of your portfolio's purchasing power in today's dollars will be $6,400,000 at age 120.
Debt will, of course, be potentially even more ruinous. Imagine if you keep making late payments on your credit cards until the interest rates get up to 29 percent and you are charged an additional over-limit and late fees of 5 percent a month!
With a longer time frame, you'll be able to be more patient with investments that will be all right in time, but which don't look very good during a downturn.
What about the future potential for income? Average productivity gains over long periods of time have been about 3 percent a year. Incomes tend to track the rate of productivity gains so we can use this statistic to estimate how much purchasing power will increase in the future. At that growth rate, purchasing power doubles every 24 years.
That is almost seventeen doublings over 400 years. For someone who earns $35,000, four hundred years of such progress would expand income to $7.5 billion in today's purchasing power. If that happens, chances are that only those who really want to work will be doing so for very long. Or perhaps the work week will shrink to a few minutes. Someone who worked 30 minutes a week would earn $94 million a year.
I think I could get by on that. How about you?
How might you earn this much for so little effort? Someone who developed a great computer program for investing money might need to spend only 30 minutes a week overseeing the program's application. Money managers are already paid in the millions if they are any good. A great one could certainly earn $94 million a year.