I once read that the late swAmI cinmayAnanda said, "Don't just believe what I say, but test it for yourself. The longer the beard, the more should be your suspicion!" His beard went almost to his waist.
But swAmI was not talking about beards, of course. He was making reference to the breadth of a teaching and how the devil (and not only the angel) is in the details.
Spiritual teaching is worthwhile when it actually helps. The point is to say what is correct in a way that leaves a constructive impression.