For some people this is actually true: life begins at forty, for others it can be at fifty, when they retire or when a momentous event occurs in their lives. Starting a new career can be daunting, but for many people forty is the perfect time to go for it.
So whatever the reason, most people do take stock and decide to "begin again" at some point in their lives. Forty is often a milestone because children are growing up and leaving home and so parents suddenly have a little more time to themselves and time to think about themselves instead of the kids for a change.
A decision to make some changes and experience a new beginning often includes the desire to make a career change. For many people, work becomes stale after a while and at forty, you may have been in the same job for almost 20 years and this is therefore not surprising.
Also, people change over time and develop new interests and concerns. For example, many more people today are worried about climate change and buying local produce than was the case twenty years ago. Careers based on the need to save the planet and ensure that we are able to provide food for are families are also more popular. And of course, technology changes and with it new careers are appearing all the time.
So the career which excited you in your twenties may no longer seem relevant, or you may be inspired by something entirely differently once you reach forty. And of course, people are living longer and with this coming the prospect of having to work longer.
Retirement was once a time for travel, rest and relaxation, but that period of our lives is now extended well beyond that of our grandsparents and for many this means a need for more money. Current employers may not wish to keep you on past retirement age and for many this is the chance to start a second career.
With job insecurity and economic instability threatening many, having a second career, starting a small business or simply gaining new skills in order to become more flexible within the job market is a necessity.