First, you don't want it bone dry. Bone dry will have your plant drooping and stressed. Second, you will get a feel for it. Pick up your pots, it will feel light without the droop at the point most here will tell you to water. I personally do not subscribe to the perpetual drying out close to bone dry as I shoot for some moistness at all times. I am in peat and I find it hard to overwater. Every water I do so to run off and whatever is not sucked back up by the plant gets discarded. Usually I am watering twice a week.
