I have asked all of my friends, and they are split almost exactly 50/50. If I kill a heroic raid boss, are they all in my vault loot table forever, or just for the week? Do you need to clear Fyrak every week to give his loot a chance to appear in my vault each week?
Killing a boss unlocks the loot table for the vault. So afaik you only need 1 kill.
Though a recent change (s2?) was that killing a boss unlocks all bosses before it, so you can’t just kill a couple bosses and gaureentee roll from a pool of 2 or 3. So fyrakk being the end boss means your vault is the entire raid loot pool if you are specifically looking for something off him.
From what I was able to read and discern from WoWhead the way it currently works is that when you kill a boss, say you kill Fyrakk and Tindral only for your vault slots, then you will roll loot from them and all previous bosses too regardless of whether you cleared them this week or not.
Supposedly when you kill them once then you unlock the corresponding loot tables permanently, I can’t confirm this. Yet I can confirm the above information is correct, and you cannot target gear by killing specific bosses.
So to be safe I would at least clear the bosses you need, given their truthfully not that hard to do.
It’s permanent.
I get vaulted weekly… Very weakly.