There are too many variables to give a straight answer.
However, lets assume the animal is of average adult size, and is still eating heavily, at the very peak of its appetite. (they will eat less and less as time goes on.)
Now, lets assume that you are feeding off crickets that are about 5 weeks old, and roughly 3/4" long. (We are going to assume this last bit, seeing is how, at least in my opinion, this would be the largest appropriate cricket Id recommend feeding. (Not that I havnt fed larger feeders than my animals should have been allowed, and not that they seemed to mind too much, but anyhow...))
Assuming these things, we could say that the assumed animal will likely eat 3-5 of these assumed feeders a day, 5-6 days a week, with nothing eaten on any off days. This would not sound abnormal to me.
However, Id like to stress how much we are assuming.
The animals environment is going to play a large role in how much energy the animal exerts daily, thusly, how much energy its going to feel the need to recoup, and how often it feels the need to do so. Its also going to effect the animals mood/stress level. This can have a large impact on appetite. The content of the feeders will effect appetite also. if you get hungry enough, you will specifically crave certain things, like the white part of a cows eyeball, or its brains. This is because your body knows what nutrients and such it needs, and can detect them when youre eating them. If a chameleon can expect to get the same thing day in, day out, its going to want something different, merely on the principle that it NEEDS something different. Such, different feeders and different varieties of gutload are required to keep the animals appetite at a healthy level.
Also, not only is evey animal different, but they are going to have heavier appetites at different stages of life.
offering more than enough and seeing what the animal eats is fine for making sure its fed, but even chameleons get fat, and have health issues from over eating. So care must be taken with that route as well.
It is a good place to start however, and will keep the animal alive for a bit while you get "used to" how much it should eat.
The best thing to keep in mind is to just know your animal, or be getting to know your animal, so you know if their appetite changes, and if you need to make changes with it.