Is the Staff of Herding consumed when used or can you use it as many times as you like?
Can you access the secret level in Diablo 3 more than once per difficulty?
Can you use the Staff of Herding to access the secret level ad infinitum?
Or is it consumed upon use?
You can use it multiple times. I've ran several on Normal, Nightmare and Hell without losing my staff. Also, When you upgrade your staff to the next level, you can still create the games from the lower levels. A nightmare staff can create a normal game.