Its not a stupid question at all. Misting serves 2 purposes...to maintain humidity over time and to provide drinking water and the chance to clean their eyes. What's the normal humidity level in the room? If it tends to be dry you may need to mist more often especially in different seasons. You'll just have to track the humidity levels with a good hygrometer to know. It will also be affected by your cage setup...how much live foliage you have, the cage temps, air flow (drafts) in the room, etc. Its good for the cage to dry out for part of the day...you don't want constant high humidity.
Basically, its very hard to answer your question because there are several factors that affect what your particular cage will do. Get a good hygrometer and start watching how the cage humidity levels change during the day, and adjust the misting schedule. You may find that one or two longer misting cycles provide the daily drink and eye wash, but if the cage gets too dry in between the cycles you may need to program a short burst to moderate that. Its really going to be trial and error for a while. If your room climate is dry (using AC in summer, heating in winter) and you will end up flooding the cage trying to keep it moderately humid, you could add in an ultrasonic fogger on a timer to sort of "fill in the gaps" between misting cycles. You'll use a lot less water and need less drainage that way.