Several decades of a decent retirement. For example, if your life expectancy is 100, you want a pension that is 50 percent of your final salary, and you save 10 percent of your earnings each year, they calculate that you won’t be able to retire till your 80s. People with 100-year life expediencies must recognise they are in for the long haul, and make an early start arranging their lives accordingly.

Like any big goal, breaking it down into manageable bite-size pieces keeps the task from veering into overwhelming. Focusing on a few key moves in each decade will set you up for a successful retirement. The last five years before you retire may be a critical point of time at least when it comes to retirement planning. That's because you must determine whether you truly can afford to quit work within that period of time. The determination will hinge heavily on the amount of preparation you have done to date and the results of that preparation.

But how to go about this? Gratton and Scott advance the idea of a multistage life, with repeated changes of direction and attention. Material and intangible assets will need upkeep, renewal or replacement. Skills will need updating, augmenting or discarding, as will networks of friends and acquaintances. Earning will be interspersed with learning or self-reflection. As the authors warn, recreation will have to become re-creation.