For me, it was always in Fallout: New Vegas. After completing Legend of the Star, the quest where you collect 50 Sunset Sarsaparilla Star Caps, I would always carry around one of the little Deputy Badges everywhere I go. In fact, I'd make the point to pick all of them up, and make sure each of the companions you can recruit, ALSO carry one. Mainly because I pretty much always play the Very Good Karma NCR Supporter.
I also make the point to, usually, carry two sets of clothes. The armor I'll use for fighting, and a set of soft clothes for when I'm around others, like NCR friendlies. Those soft clothes usually include a beret and sunglasses.
I doubt hoarding one of every armor set, and one of every weapon, unique or modded, counts though. But I always do, keeping them in different containers around the Suite at the Lucky 38. Of course, that's separate from the armor and weapons I'll actually wear and use.