Personally, I don't like to clip wings on mine unless I have to. The ability to fly even a little could mean the difference between life and death if a predator got after them. They are contained in a huge yard by a 4' fence. However, there are a few trouble makers now and then that refuse to stay in and I have to clip a wing to keep them where they belong. It is usually youngsters, and I rarely have to clip them more than once. (The feathers will grow back when they molt.)
As to how high they can fly, it depends entirely on the breed. My heavy breeds can't even get high enough to get on the 4' fence, except when they are youngsters. My little d'uccles on the other hand, can fly REALLY well. They routinely get on top of the coop and on top of the barn. They could very easily get out of their enclosure. But they never do, once they learn where their allowed boundaries are.