Jobs that don't require a long education are usually referred to as vocations rather than professional careers. It would not make someone an expert in a subject

Jobs that don't require a long education are usually referred to as vocations rather than professional careers. It would not make someone an expert in a subject area. Airline maintenance is a good example. Quick to learn and high paying, but it would not make you an expert in either aviation nor engineering. In the US, to testify as an expert in court, you need to have spent 20 years at your profession.