'Do I really need my savings to last until I'm 100?'
(MONEY Magazine) -- Why do I need my savings to last to age 100 if my average life span is much shorter? -- Mike Johnson, Fairfield, Ohio In "The Flaw of Averages: Why We Underestimate Risk in the Face of Uncertainty," Stanford management-science professor Sam Savage illustrates the folly of planning using averages by recounting the tale of the statistician who drowns crossing a river with an average depth of three feet. The rub, of course, is that while the stream is shallow near the shore, it's 12 feet deep in the middle. The idea of using your average life span for estimating how long your savings will have to last in retirement is similarly all wet -- and could leave you in the unpleasant position of having no savings but a whole lotta living to go. Life expectancy isn't an estimate of how long you are likely to stay alive. It represents the average number of years a person of a given age is expected to live. These days, the life expectancy of ...