I recommend getting a fecal right away. Sometimes your Cham comes to you with parasites. They get parasites from the insects they eat and some parasites such as coccidia are highly contagious. I don't even wait 6 months on mine. We get fecals here every 3 to 4 months and 90% of the time somebody has something. If parasites go untreated eventually they will kill your Cham.
The kind of Coccidia that chameleons have is contagious only to other reptiles.
I always collect a poop the day before just incase they refuse to do one the day of the fecal. If they give me a fresh one the day of I trash the old one. I turn a zip lock bag inside out and pick up the poop. Turn the bag back correct and close. Keep in the frig until you are ready to take to the vet. The fresher the poop the better.