It takes about 6,400 hours of class time and studying to get a 4-year degree. Assume that it takes you only 5,000 hours to master your field.
While you are happy that you've prepared for your profession, the knowledge you've learned is fast becoming outdated. We can safely assume that in 10 years, 50% of the facts in the field would be outdated. This means that for you, just to keep up in your current field, you'd need to learn 5 hours per week, 50 weeks a year.