When you have a clear cast in WoTLK Gold proc for arcane it is best not to repeat the casting unless you feel believe that the mobs moved forward, as the rest of the time Blizzard is benefiting from the 30% chance of success from the arcane potency. Also, because of its ability to Blizzard can clear cast many times.
That's why it's so wonderful. The other benefit of AOE and knacks is it's just really man efficient, because each time you cast it, there's an excellent chance you're going to get an unambiguous casting product from it.
So you can just most of the time be varied based on the amount that mobs are Blizzard into the next free cast or man and Blizzard like you see in this video, I've been blizzarding all this time and WOW WoTLK Classic Gold will not continue to.