I can always tell when someone is an expert in their field.
I know because when I ask questions, they answer flawlessly, and they are able to make their way around their machines as if they were born to do it.
The example I am thinking of is the HVAC professional that comes and does our HVAC maintenance every year. We have a HVAC tune up in the spring and the fall, right before the harsh seasons. Out of curiosity, and slightly because I wanted to test this heating and cooling specialist, when he first arrived at our home, I asked him some A/C questions, some difficult, and some easy. He answered them instantly and was correct every time, I was impressed. Now, why would I bother asking a HVAC worker these questions, I mean, they are a heating and A/C worker, so they should know what they’re doing right? Well, not always. I have in the past had heating and A/C specialists that would come to my home, and they would have no idea what they’re doing. I would watch them from my window work on the central A/C, and some of these cooling “professionals” would be poking at the cooling component like it was a foreign object. Shaking my head, I made sure to start asking questions to the cooling techs at the start. I want an actual certified cooling technician. Thankfully, like my current A/C technician, there are some fantastic cooling professionals that know what they’re doing.