How do you know...

When do you know to move on to the next level of education? This does not have to be strictly pertaining to primary or secondary school. It can include a hobbie, passion, secret pleasure or your every day career. I believe that you should study what you are working on until you can do it backwards and in your sleep. Once you can do that, it is important to study even further into it. It is similar to the way the Japanese live their entire lives. The pursuit of perfection is an on going and lifelong endeavor. You are well on your way when able to teach that single skill to someone else successfully. 

What do you think? How do you know?