If you have to mist your cages daily to keep decent humidity, you have too much air flow. I personally prefer the chunkier coco stuff like ReptiChips. It seems to hold water better and longer. The coffee ground stuff seems to dry out really fast. In my AP T10 and T8 cages, if i put in 1/2 deep Reptichips in there, i will have humidity spiking to 100% for days.
Even with aspen, i generally only give it a good misting once or twice a week in the winter.
To answer your question, you mist the stuff whenever it dries out and the humidity drops. It will vary from cage set up to cage setup.