that's more or less up to you, how your set up is built and how much water your set up can handle.
But... there are some basic guidelines:
You want things to dry out over night, so make your first mist shortly after the lights come on (give him time to warm up before spraying him with possibly cold water)
I also have my last mist come on a hour before lights out to help things dry out good.
My set up can handle a decent amount of water and I have NO DRAINAGE system. Most of my mist gets funneled into by baby tears plant or evaporated off the leaves. I have my mists set for 1 min long and up to 1min 45sec at a time. I also a dripper which drips about 4-5 drops per minute (1 drop per 10-15 sec) and that's plenty to keep standing water on my golden pothos.
I also have a humidifier plumbed to put humidity inside the enclosure, its on a few hours before lights up and off a few hours prior to lights off.
I tend to have most moisture in the morning (after I leave= no opening closing door disturbing humidity) and let things become less humid in the evening when im around. So I would mist at 7am, 8am, 9am, then switch to 11am, 1pm, 3pm, 5pm, 7pm. for 8 cycles.
I find this to make the most sense in programming intervals. But for how long is up to you.
I have a to veiled chams make and female it's a screen cages don't know the sizes but te makes better then the females and no I don't have a dropper only mister
You need to work on your grammar, im not exactly sure what your trying to say. you have 2 veiled's. 1 male and 1 female. You should be careful of this, im not too sure if housing chams together (even if they are opposite sex- if your planning on mating you put them together only for short time) is a good idea.
Generally you don't want 2 chams in the same enclosure. You may need to get some sort of dripper system going, to be sure they have adequate water to drink as well.
Sorry about that. What I meant to say was that I have two veiled chams. They are in different cages. One is male and one is female. I don't know the exact size of the cages either.
okay, that's fine. You should preferably have some live plants in your cage, it will help will humidity control and dispersion of drinking water for your guy. Mist as you see fit, but you should have a dripper running as well. Unless your around enough to manually disperse water or mist.
Live plants, especially one that can have a base at the bottom will allow you to have a dripper going above it, and have it run into your plant. Misting is good for maintaining humidity and getting a large coverage of water on leaves for him to drink, but it quickly evaporates.
Most misters will spike the humidity up to the 80% mark but fall down to ambient humidity temps within an hour or so. Depending on what else you have going to maintain humidity. Some can last much longer.
In a perfect situation you would have:
A humidifier going to maintain humidity throughout the day (and night if needed)
A dripper going during the daytime (some people just drip in morning after mealtime) but I have mine going with the lights.
And A Mist system, for bathing, drinking and humidity spikes. Also helps with cleaning.
Live plants are a great factor to enhance all three of these devices as well.