In a vocational school, you can be exposed to about 124 products in about two months of study. Not only that, you can also learn about raw material supply, business management, marketing methods, etc. In a bar or self-study, it may take 2-3 years to become a master. In a bar, you mainly start from doing odd jobs. It may take 4-5 months before the master will start to teach you useful knowledge and mixing techniques. Self-study is even more difficult. It wastes time and remains in the clouds, and the efficiency is extremely low.