There have been many articles and blog posts over the last several years about the ability to delay your Social Security retirement benefit start date in order to increase your monthly benefit. I wrote about this in my March 4, 2013 post, Increase Your Longevity Risk with Social Security. Per the post, with a choice of start dates ranging between 62 through 70, you can increase your benefits 7% - 8% each year that your start date is deferred, excluding cost-of-living adjustments ("COLA's").
Sources of sustainable lifetime income are few and far between these days with the widespread elimination of monthly pension benefits. The ability to receive a stream of sustainable lifetime income throughout retirement while also choosing your income start date is a rare planning opportunity, the value of which shouldn't be underestimated.