Hi,
I am not sure how dry it gets where you live but I live in Canada and the winter gets very dry. First of all, you need a cage with small side vents and absolutely no top opening or screen. Even with small vents, you still need to open or close some of the vents to ensure proper balance between humidity and ventilation. In the winter, I use a room humidificator to bring up the humidity of the room to at least 50%, then I spray my cages twice a day during the dry season (once a day in summer).
Playing with the vent holes takes a bit of experience but is relatively easy to master. Keeping the humidity of the room up is much harder. I have to refill the humidifier every other day, it runs at least 80% of the time and it is a very very fine balance between humidity and mold in the room(humidity condense on the cold walls and cause molding...I make sure I leave the closets open and that nothing is touching the wall so that it gets ventilated...this may not be a problem for you in the desert)...and the humidifier is pretty much worn out after one full season...