Millions of retirees rely on Social Security, yet a surprising number claim their benefits as early as possible. Given that waiting can boost your benefits substantially, why do so many refuse to consider waiting?

In the following video, Dan Caplinger, The Motley Fool's director of investment planning, goes through three factors that explain why so few retirees wait to take Social Security later. Dan notes that with most breakeven dates for payouts extending 10 to 15 years into the future, many new retirees aren't able to conceive of living such a long time. Dan then points out that most people have already delayed their plans for retirement by working longer, and further delays aren't something many retirees are even willing to consider. Finally, Dan observes the fear that many benefits recipients have about Social Security rules changing. Dan concludes that even though some of these fears are more valid than others, the net result is that many won't take full advantage of the protection Social Security offers.