It's the kind of question that confronts most men and women at some stage of their life and career. And especially when they have reached the top. Because the top is scary. It is stressful. And as soon as you reach the top, the other more important question that confronts people is 'how long can I stay here?' Imagine that after striving all your life to get to the top, there is still another question to torment you. While the question itself in many ways fuels man's ambitions and desires, it is ironical because it's also responsible for Man's fall from Grace as it were, to borrow a metaphor from the Genesis creation narrative. People who don't retire in time, have every chance of falling. 
Often our egos and our attachments make us go and on. Most people are unwilling to give up their place at the top because it needs the courage and an ability to say, "I have had enough and its time to move on to other things". It is the fear of how to replace a demanding job and career and figuring out a substitute to fill that void. People with hobbies and passions besides their jobs may find it easier to give up the hectic pace demanded by one's profession. Those with hobbies often feel unfulfilled during their working life, because they are unable to give their best to it. Both energy and time get released once they have retired to pursue their interests. People without any hobbies are forced to find something new to do which can consume them. A good example is Bill Gates who has devoted himself to philanthropy and causes that affect the people of the world. A really honourable thing to do. (This is not to say he doesn't have a consuming hobby, he probably does)
Hang your boots when you are at the top
Many in their attempt to stay at the top, get toppled but keep pursuing their dream of getting to the top once again. This is more common in sports. For example, Mohammad Ali is known to have come back to reclaim the boxing crown a good three times in 1964, 1974 and 1978. But each time he lost the crown, the world skipped a beat, worried if he would really make it back to the world championship, and I am sure he must have skipped a beat as well. Going back the second and third time seems tougher than the first time especially in sports, if only because the body grows older, increasing the degree of difficulty to achieve the same level of physical endurance. One can see the struggle that Tiger Woods, for example, is going through to try to get to the top again. Getting back to no 1 from his Official World Golf Ranking of 650 is going to be no mean feat. Retiring at the top seems to be all about good timing. Sachin Tendulkar, for example, seems to have got his timing as right as his batting.
However, in fields where physical prowess is not a requirement, people do pursue their professions late into life. A good example is musicians. Take for example jazz saxophonist Wayne Shorter.
Jazz Saxophonist Wayne Shorter
At eighty-three, he is as good as he always was. In fact, he even won a grammy just 3 years ago in 2013 for the best jazz instrumental solo for"Orbits". So the question of retiring just doesn't arise. At best he probably can't stand as long as he could but is happy blowing away on his saxophone by sitting on a chair.
But some of the most difficult questions to answer seem to be 'will I have enough money when I retire?' 'Will I miss all my relationships at work?' 'How do I replace all the time I spent at work? and 'Will I get bored'. Most people who went back to regain the top seemed to have enough money to last them a lifetime. But then man's desire is eternal.
Nico has a very good reason for retiring - to spend more time with his wife and one-year-old daughter. Retirement was about restoring the balance in his life. In the process, he gave up more than $18 million due to him in the near future. A sure sign that for him the sacrifice was well worth it.
But then man's yearnings and desires are eternal. Not everyone will find it as easy as Nico Rosberg to settle down to a quieter life.
---------------
About the Author:
Prabhakar Mundkur is an ad veteran with over 35 years of experience in Advertising and Marketing. He works as an independent consultant and is also Chief Mentor with Percept H. All previous posts of Prabhakar can be found here.
'Life would be tragic if it weren't funny' Stephen HawkingOr take Stephen Hawking for example who has confined to his wheelchair for the longest time and yet has so much to share with the rest of the world on how the universe works. The Eternal Questions about Retirement