Decor Question

I’m pretty confused about how obtaining “old decor” from vanilla, cataclysm, wrath, etc. works.

I have The Loremaster title for instance, and so theoretically, across several characters I have completed all of the quests in the game up to Dornogal. So, if I were to log in on these individual characters, would it unlock items from quests I’ve done?

I ask because, I just made a new Paladin and I was doing the early quests in Northshire Abbey, and I was getting housing items at the end which were giving me a first time completion bonus, despite knowing that I have done these quests before on other characters that I have already logged in with.

How does this system work, or do I need to make a new character and start my journey over, or go back on another character and do these quests?

Thanks!


ETA: This is specifically for typical quests, not rep-related decor. I understand that if I’ve unlocked Exalted on a character, I can buy all of the items from the rep vendor.

I’m just curious if I’ve done a standard quest, like hunting 10 bear butts 20 years ago, and I log into that character today, does that give me the keg, or do I need to redo the quest on a new character to get the keg?

I hope that makes sense.