We all ponder this question, especially when developing retirement plans. This unknown is a variable that creates real challenges for most of us when it comes to calculating how much we can spend and the income we will need to support our spending assumptions.  

Retirement research Wade Pfau recently authored a Forbes article, Changing Risk in Retirement: Unknown Longevity, that addressed the issues of longevity. In it, Wade referenced a longevity calculator from the Society of Actuaries that can help you estimate how long you (and your spouse) may live.  

Note: The Forbes article is an exceprt from Wade's latest book: Safety-First Retirement Planning. It's an excellent book, especially for those seeking to learn more about retirement income strategies.