I was going through my inventory to sell to a merchant and ran across some items that sound like they might have been quest related items, but I don't remember: People's Journals, Warsworn Ranks, Graveside Letter, etc.
Do I need to be worried about potentially selling something that I would need to complete a quest?
I think the answer by Vinay might be wrong. There are papers you pick up that are tied to unimportant quests that it will let you sell or destroy. I think the only ones it won't let you destroy are main quest papers. Whether or not you have to have them in your inventory or if all you have to do is read them to kick off the quest I couldn't say. I think they have to be in your inventory.