Life expediencies have been rising by up tothree months a year since 1840, and there is no sign of that flattening. LyndaGratton and Andrew Scott draw on a 2009 study to show that if the trend continues, more than half the babies born in wealthier countries since 2000 mayreach their 100th birthdays. With a few simple, devastating strokes, Grattonand Scott show that under the current system it is almost certain you won't beable to save enough to fund several decades of decent retirement. For example, ifyour life expectancy is 100, you want a person that is 50 percent of your finalsalary, and you save 10 percent of your earnings each year, they calculate thatyou won’t be able to retire till your 80s. People with 100-year lifeexpediencies must recognize they are in for the long haul, and make an earlystart arranging their lives accordingly.

But how to go about this? Garatton andScott advance the idea of a multistage life, with repeated changes of directionand attention. Material and intangible assets will need upkeep, renewal orreplacement. Skills will need updating, augmenting or discarding, as willnetworks of friends and acquaintances. Earning will be interspersed withlearning or self-reflection. As the authors warn, recreation will have to becomere-creation.