I've got myself into tanking recently, and been tanking hc regularly (used to raid heal). I pugged my way through most of all them hc's. But the few times I got with a new healer, I started using my buttons. This actually made me wonder.
We have 4 "panic" buttons
Survival instincs (glyphed on that one)
Frenzied regenaration (also glyphed here)
Healthstones/potions
and at last, barkskin
But barkskin is only a one minute cooldown. Is it worth using it everytime it gets off CD? Or should I use it for "oh, crap" moments only ?