You know it's time to look for the second curve when you don't enjoy your work as much as before:

• You feel your competence declining.
• Others close to you notice you're not as sharp as you used to be.
• Other people receive the social and professional attention you are used to.
• You have to decrease your workload.
• People you meet don't recognise you or your previous work
• You feel like no one.

Moving toward the second curve:

• Evaluate and improve relationships. You'll be good at that.
• Don't wish for something better, work for what you want.
• Value and hire for wisdom in the C-suite and on boards.

Ageing isn't all bad news. In some specific ways, you'll get smarter and more skilful. The trick to improve is understanding, developing, and practising your new strength.

• As people age, their vocabulary and grammar increase. They are better Scrabble players and can do well in foreign languages.
• With age, people become better at combining and using complex ideas. They may not be that good at coming up with new inventions, but they get much better at expressing and interpreting existing ideas to others.

People possess two types of intelligence.

• Fluid intelligence is the ability to reason, think flexibly, and solve problems. You learn quickly, focus on what matters and create solutions but can't maintain this as you age.
• Crystallised intelligence relies on a stock of knowledge. It increases through middle adulthood and does not diminish until very late in life.

If your career relies only on fluid intelligence, it will peak and decline early. But a career that requires crystallised intelligence will find that decline happens much later. If you can go from one to the other, you will thrive.