It’s hard to predict when you’ll enjoy your most productive periods in life. For some people, their years of productivity come early, and then they just ride out the remainder of their lives based on early successes. Albert Einstein, to take an example, was one of those people. In fact, most major scientists seem to achieve their major breakthroughs before they reach the age of 50. After that, there seem to follow decades of “coasting” on past successes.