In general orchids that require a dry rest will grow in their season (many make their growths in spring-summer) then they will complete that growth. This is when you start to reduce the water. Instead of watering them as soon as the mix dries out, you will start to wait more days before you water again. This is also when the temperatures drop as well, so the mix will also take longer to dry. Anyway, basically just watch them for signs of dehydration and don't let them get too wrinkly. Some of the dendrobiums really like to dry out, but I can't really give much advice on those. I just grow cattleyas. Anyway, usually they will start growing again in the spring and that is when you start increasing the frequency of watering. Just watch them and listen to them. They will tell you what they need.