Ideally, they are supposed to be two different things. When I went to school, we learn and practiced the things that you did not normally learn in the field, so that when you ran into them, it was not a surprise. In the field, you are applying a very limited amount of the plumbing codes scope.: I am an apprentice at a small company. What is the advantages of learning plumbing codes at work as opposed to in the class-room?