Re: Internal strength in bowling, fencing, golf, etc.
Before one brings up the analogy of Roger Ebert critiquing a film and the relevance of his film experience, let us not forget that he is a Pulitzer prize-winning author with actual experience in the film industry (he wrote Beyond the Valley of the Dolls -- say what you will about the quality of his output).
I'm also sure there are plenty of people in the industry that think to themselves, "Ebert, what the hell has he ever done . . .?" I also don't think that people working in film look to Ebert for validation other than to see how other people that DON'T work in the industry react to what he has to say (i.e. whether or not people are likely to come see the film based on his review).
If your audience/peer group is comprised of people that DO have extensive experience in related areas of discussion, then your own experiences do factor in to the amount of validity that's weighted to your contributions.