The lesson is, never stop learning.
Kyusho is something many seem as a finite study... once you know the points and the ways to hit them, you are done.
Nothing is ever done... there are so many variables and infinite ways to apply and transition from other points, there can be no end to learning.
But the real lesson is not just in learning new ways to use known points, it goes much further as each "discovery" leads to greater potential "discoveries" for all other points as well.
It is critical to consistently push your known boundaries so that you do not stagnate, as when no movement is present decay manifests.
As a side note, when people age, they retain their mental faculties far better when always challenging their minds and learning. Crossword puzzles are one way, but learning more about the body they and everyone else is in adds greater depth and use in life.
Challenge yourself everyday.