How many years exactly?

Mastery takes time but should not take forever, and mastery does not always mean perfection. Perfection is what is hard and impossible to achieve in trading, but mastery is not. The difference between the two is that in perfection a trader records no losses at all, which is something we know is almost impossible. In Mastery, you win a lot more trades than you lose, and that is the stage most traders get to.