But even if people are able to economically support a retirement at 65, over thirty years of potential inactivity is harmful to cognitive and emotional vitality. Many people may simply not want to do it.

A multi-stage life will have profound changes not just in how you manage your career, but also in your approach to life. An increasingly important skill will be your ability to deal with change and even welcome it.

In a three-stage life, people leave university at the same time, they tend to start their careers and family at the same age, they proceed through middle management all roughly the same time, and then move into retirement within a few years of each other. In a multi-stage life, you could be an undergraduate at 20, 40, or 60; a manager at 30, 50 or 70; and become an independent producer at any age.

A three-stage life has few transitions, while a multi-stage life has many. That is why being self-aware, investing in broader networks of friends, and being open to new ideas will become even more crucial skills.