I tend to sort things.
In Oblivion, I get houses with lots of shielf space so I can sort the potions I make and find. But, I also rarely use them because somewhere in the back of my mind, I'll need the more later. Of course, by the time that does come up, the potion is hardly worth the effect because I've leveled up so much.
Same goes for Fallout: New Vegas. Thankfully, the hideout that I use has a bunch of auto sorters in it. So, it isn't nearly as big of issue.
Even in Team Fortress 2, I keep my backpack very neat,Sorted by class then weapon slot. I also like keeping as full of set of weapons as I can. At this point, I'm only missing three and I can craft two of them if I really wished to do so. There is just something that says, when I go to craft or trade a weapon that I only have one of, that I will need it for some reason. It doesn't matter if the weapon is next to useless for how I play the class, if I play the class, I must have it!