It all depends on the species you have and the humidity level. If you have more live plants Then the humidity will be higher and will stay humid for longer periods. Make sure that it sprays on some plants as to create water drops for the Cham to drink from.
I have a panther chameleon (nosy faly) , I have 3 pothos (if that's how you spell it), I've made sure that there are plenty of droplets. Only on half the cage, so there is a dryish area if needed
I started off at 1min 4 times a day as I have a wooden viv and I thought it would pool water but it didn't so I have extended it to 1.5 mins and that does the job.
I'm sure you will love it.