If you wait until 70 to collect and live to your mid-eighties, you win big. But who says you'll make it that far?
FORTUNE -- Year-end festivities are approaching, with Hanukkah lights nearing their peak, Christmas lights going up, and the New Year's celebration almost upon us. So what better time than the season of light is there to talk about ... mortality?
No, I'm not raising this gloomy topic just to be contrarian at a time of widespread celebrations. I'm raising it in Fortune's Investor's Guide because one of the most interesting investment decisions that you may have to make (or may have already made) involves estimating how long you're likely to live.
This decision doesn't involve stocks or bonds. It involves Social Security retirement benefits.