Through a combination of training and experience we all develop specific expertise over time.  This is a skill and knowledge in a particular field.

In many cases professional credentials are associated with this expertise.  For example a journeyman plumber, medical doctor, certified accountant and so on.

In somes background and demonstrated knowledge (for example authoring a book or a specific role) are the only supporting evidience.

Skeptism

Sometimes experts rely on their background to support suggestions and recommendations.   In the Corporate world consultants advice is sometime taken based only on their reputation.

 Regardless of the nature of the experts input, (whether it is a repair, direct action or just a recommendation) it is wise to exercise some healthy skepticism.

Obviously training and experience are valuable indicators of  quality but regardless of the credentials there often are optionxs and the experts input is just one opinion.

Pet Peeve

I frequently notice those designated experts are annoyed if I do not immediately bow to their greatness.  How dare I question them, after all they are the subject matter expert.

In context, while training and experience are invaluable, they are not absolute.  Consideration of supporting arguments and logical analysis are still needed to supplement the expert opinion.

In many cases there is no single absolute right way.  In these cases debate and argument to support the expert conclusion is a reasonable expectation.

Sometimes I wonder is the so called subject matter experts need for their input to be accepted is as much about self justification as anything else.