Generally, an instructor masters one focus and teaches that. It s for you to decide which focus you want to learn and to find the right school. Going back to the construction analogy, by knowing about the four focuses, you will be able to tell the difference between, plumbers, electricians, framers and carpenters, and hire the right one for the job. These different focuses have profound effect on what you learn. They also have a profound effect on whether or not you stay at a school.
Many people come to a school and want to learn a particular focus.
They leave feeling frustrated and betrayed because they were taught another. If you walk into a school where the focus is different than what you want, you're in the wrong place. It may be a great school, but it's not the right one for you. Odds are you'll just end up wasting time and money. Don't buy the sales pitch of an instructor who claims that his school teaches all focuses.