So I guess the answer is... depends on how many of the classic symptoms they can observe easily, how many positive test results you have, and how good the doc is.

Oh, and how long you wait in between seeing docs, if one is disappointing. I had a disappointment over a year ago, and I'm still unsure if I'm ready to spend time and money to see if another doc will diagnose me.

Not as much because of loss of time/money/effort. That matters but more because of the possibility of emotionally being let down or them even attacking me by saying I'm imagining things.