Originally Posted by
Reev
You shouldn't use Shield Wall every time it's up, but you should use it very very often. The more you learn to identify higher damage phases and use your cooldowns to help healers, the better off you are. Paladins don't usually have to use a cooldown because it's built in. Warriors have to be a bit more proactive. So when a worm soft enrages on Beasts, pop your shield wall. When Icehowl is coming out of stun and you know he's going to headbutt stun you and hit you again, use your shield wall or last stand. When you're tanking Burrowers on Anub'Arak, and you have 2 of them at the same time, pop shield wall. If you have it talented and glyphed, it comes up often enough you can use it very very often, and should.
The worst thing you can do with shield wall is to save it as some sort of panic button. It's there as a proactive mitigation tool and should be used that way.