do you take your cham to the vet for a fecal?
My chams are all tested yearly, in October. I choose October because I use a lot of wild caught feeders over the summer (June - Sept) more than in winter, thus increasing parasite risk.
I will additionally take in a sample if anything seems "off" at any time of year.
I have sufficient years of experience, and keep extensive logs, so I feel comfortable that I would notice an issue sooner than a novice keeper might.
I suggest novice keepers (those who have had chameleons less than several years) take in fecal samples every 6 months. Its quite inexpensive, and catching something quickly/early can save a lot of money and heartache.