The 80/20 rule is definitely the way to go. Relying too heavily on formal training without ever applying that training to actual problem-solving is like trying to learn to fly just with ground school and no time spent at the controls. Students learn by doing, they learn from instructors, they learn from each other, and they learn from their own mistakes. Classroom training is invaluable, but it's only the jumping-off point, not the total experience.
