I find using basic common sense is expected a bit too much from Arms warriors!
No really, the usage of HS should be of a "getting rid of it" mentality.
You don't want to use HS in itself you only want to use it to either get rid of too much rage (which rarely happens for me atm, especially when fighting 2+ targets) or to get rid of 2+ stacks of TfB.
The reason I say 2+ stacks is purely subjective - it makes my life easier to worry about HS in as few circumstances as possible - use HS just ONCE too often in a fight and you're rage-raped for the next 20 seconds.