Do you need to hear an "expert" say something to believe it?

Do you need an expert opinion regardless of reason and logic? I’ve recently heard some folks basically express that fact, that basically it didn’t matter if something made sense, they needed an expert to sign off on it. I guess what that meant was one of their approved experts.

And even more importantly, how well do you check up on the things said experts express, particularly in terms of “facts” and statistics? Do you apply the critical eye? Logic and reason? Often the more poorly researched opinions get posted first, the later rebuttals taking time because it takes real work. Sometimes one theory is given more credit simply because it’s “advertised” better, or tells people what they want to hear. Even professionals fall into this trap.

“A lie can travel halfway around the world while the truth is still putting on its shoes” – Mark Twain

Some of this, of course, goes back to the question I asked recently about premises.