Lakeforkguy,
A lot depends on the water clarity, overall depth and the level fluctuation of the lake you fish. The clearer the water, the deeper you need to put them. Here on Kentucky Lake, we have found that, on average, 10-12 feet is a good all around depth but water clarity changes depending on the rain and runoff and the level changes 5 feet from summer to winter. We have beds in 7 different bays and we have to fish each bay a little different from the other. Some, on average, are shallower than others and some have a deep creek channel next to shallow water and some don't have much definition at all. But when we start putting stuff in a new bay, we start at 10-12 feet. Hope this helps.
The only way to have a good fishing spot is to make it yourself!