Well, first of all, we called ALL OVER the Puget Sound area to find vets that were experienced with chameleons. There were several, so that was good.
For his first visit, Guido went in because he was restless, had lost interest in food, and had fallen off his vines a few times. The vet handled him as though he handled chams all day. He was very familiar with their anatomy, how they stored fat, etc. He found Guido to be in good health, with strong grip, but that he had reached sexual maturity and was experiencing something of a male estrus. In other words, he was wandering around preoccupied with looking for a mate. He did prescribe panacur, to be taken as prevention, since Guido came from a pet store and had not been treated for parasites. We did not have a fecal done, and now I don't remember why. Anyway, Guido was fine, and the diagnosis appeared correct. We purchased a chameleon shaped beanie baby on eBay, gave it to Guido, and they settled down to wedded bliss.
The next time he went in (2 years later), his symptoms were also quite vague, but he was recovering from an impaction he had passed weeks before. The symptoms were occasionally sleeping during the day, a slight chronic eye problem, and basically laying around on his belly with his chin resting on the perch. His vet was on vacation, so we took him to another herp vet up north. Again, the vet handled him as though she saw chams all day, said he was in good health, just a bit overweight (which we already knew and had already cut back on his food). The vet told us how to adjust his diet, and prescribed an antibiotic for mild systemic infection, did a blood workup and fecal. The fecal was clean. The bloodwork showed an imbalance of the Calcium vs phosphorus, which possibly caused the eye problem, and the other issues.
So, we adjusted his diet to get a better balance, gave him the course of antibiotics, and he rebounded incredibly fast, back to his old rambunctious self.
So, I would say that both trips to the vet were well worth it. Of course, we learned with each visit, and now there are some problems we will be able to avoid, or treat by ourselves. The first trip to the vet was perhaps unnecessary, but we did learn about panacur. The second trip to the vet probably added years to Guido's lifespan because of the changes we made in his diet.
The one thing I did not like, was that at the second vet's the assistants wanted to hold Guido, who was shedding at the time, and they kept pulling bits of shed off of him. (I thought it wasn't good to tear at a chams shed skin because you can cause problems if it is still attached to unshed skin.) I asked them not to do that, but they said it was OK and persisted. So, be forewarned, just because the vet has experience, a new assistant may not have the same degree of experience.