I read somewhere that a bookbinder has to make at least 100 books before they can claim to have the necessary skills to do quality work. Each of the 100 books is intended to provide one or more lessons in what not to do.
The 100 Book Rule
Mastery and the Art of Starting Over
Over the course of 2018, I read books about mastery. Every book hammered home the same point: You cannot master anything that you don't feel passionate about. Learning a profession, any profession, requires hours of commitment to learning, failing, practice, and mentorship. 10,000 hours is the number the experts say is required to "master" a skill. But according to my study, the hours alone are not enough.
Of Paper and Ink 