Will you still need me, will you still feed me, when I’m 64?
– “When I’m 64,” The Beatles (1967)
The character intoning that line in Paul McCartney’s famous song about growing old must have been confident in his longevity: According to the U.S. Census, the average lifespan for a male in 1967 was 67 years and for a woman 74 years. From a strictly Census data-standpoint, there might not have been many years left to “rent a cottage in the Isle of Wight” or spend with the grandkids, “Vera, Chuck and Dave.”
Incidentally, McCartney turns 71 this month and still performs on stage with a vigor that would have been rare for a man his age 45 years ago. Sixty-four isn’t considered “old” anymore, and each year our definition of “old” continues to change. Currently, the Census Bureau’s projected lifespan in 2015 is 76 years for men and...