[AndrewOMartin]

> Hire someone that knows what they are doing

How does a non technical person tell someone who knows what they're doing from someone who is good a looking like they know what they're doing?

I'd like to use your answer to justify my purchasing decisions when I need work done on my house/car/genes.

[riskneutral]

A closer analogy would trying to hire someone "that knows what they are doing" (whatever that means) when you need the work done at 2am, in the midst of a crisis, on the side of road, while your house/car/genes are burning down.