This underestimates longevity a bit: a 55-year-old in the US has a life expectancy of ~26-29 years (male and female, respectively).[1] Granted, this may hinge o

This underestimates longevity a bit: a 55-year-old in the US has a life expectancy of ~26-29 years (male and female, respectively).[1] Granted, this may hinge on what you mean by "active" years. [1]: https://www.ssa.gov/oact/STATS/table4c6.html https://www.ssa.gov/oact/STATS/table4c6.html