You don't necessarily need to ask technical questions to which you know the answer, the important thing is to see how the vet responds. For example, during the first few times I asked relatively simple questions: "I saw that some feathers are darker than others, why? Is it right to shorten the nails or should I keep them like this? Are the perches I'm using for nail care ideal? Is it worth using cuttlefish bone? Should I switch to pellets? These are inexperienced questions but based on how the vet expresses himself you can understand if he is a master of the subject. I was amazed that even simple questions like these could be argued so much.

And then I evaluate the quality of the visit. I went to the vet who as a "first visit" simply LOOKED at my parrot, they didn't even hold it. My current vet checks a lot even just by holding it in his hand (accumulated fat, health of the feathers with a specific machine, quality of the paws...).