I suspect young ones might poop daily, but for adults it's not at all unusual for them to only poop a couple of times a week.
There might even be some relationship between feeding and pooping...you feed them so they feel comfortable releasing what they've been holding inside.
And, as with just about all animal species, there are variations to the "norm"....you might have a chameleon who is perfectly healthy but only poops once a week. That's why poop peering alone is not enough.
The white is the urate and it should be white or creamy colored. If there's just a bit of yellow or orange at the tip, that's not a problem. If the whole urate is visibly yellow or orange, that's bad and needs help.
Do note, however, that if your chameleon is one who doesn't poop a lot, then the urates might be more yellow/orange even though hydration is fine...that's why you are smart to monitor the frequency of pooping.