Social Security’s life expectancy calculator predicts I’ll live to about 86. An insurance company’s version says I should expect to die at 98. A longevity calculator created by actuaries demurs, putting the odds at only 32% that I’ll make it to 95.

Eventually, I’ll find out which life expectancy calculator was most accurate. In the meantime, the different results help illustrate one of the most important and difficult calculations in retirement planning: figuring out when it will end.

In my latest for the Associated Press, why life expectancy matters.