One way to financially plan for longevity is with longevity insurance, also called lifetime income, also called lifetime income annuities. The most common form of lifetime income in the USA is called Social Security, and nearly everyone in the USA will claim Social Security in the later years of their life, normally starting in their 60s or 70s. Another popular sort of lifetime income is to get a pension from an employer who offers them. (Unfortunately, there have been some scandals with some employers not properly funding their pension plans.) Finally, if someone wants more lifetime income than what they can get from Social Security and/or pensions, another option is to go to a reputable insurance company, preferably one that's been around for over 100 years, and trade a lump sum of money in exchange for a guaranteed income for life, backed by the claims-paying ability of the insurance company.

Disclaimer: We are not medical professionals and the following is not medical advise, just statistical analysis.

Where this gets really interesting is that having a lifetime income annuity is apparently correlated with increased longevity. One possible reason is that people with cancer are probably much less likely to buy annuities, whereas healthy people who expect to live longer are more likely to buy them. However, to remove that sort of selection as a variable, researchers looked at data from the Civil Service Retirement System (CSRS), "a defined-benefit plan for federal employees that pays a lifetime annuity to retirees based on their years of service, among other factors." You can see some of the data below.

According to Patrick C. Tricker, "Table 1 generally shows mortality rates decreasing as the amount of the monthly annuity payments increase. Table 2 shows that this trend holds even when the data are divided up based on final salary. Some exceptions to this trend exist, but these deviations appear to result from natural statistical variation."

Tricker continues, "In some cases, the differences in mortality rates are highly significant. For instance, among retired individuals under age 76 whose final salary was between $40,000 and $60,000, those individuals with a monthly annuity of above $3,000 had a mortality rate 33 percent lower than the average individual of the same age and final salary range who received an annuity of less than $1,000 per month. Final salary is not a perfect proxy for wealth and income, but it is a strong one. Hence, these results suggest that the incentive effects of a life annuity increase the life expectancy of the annuity’s owner."