When designing your unit blue prints or equipping your hero, you have the item filters. Along the top you have [ALL][WEAPONS][ARMOR][ACCESSORIZES] and then on the bottom you got [SHOWOBSOLETE][MISSINGRESOURCE]



There really should be a button that allows you to sort out all the non-quest items. Are are little head-ache moments when you have to equip an item for a specific quest but cant find it on the inventory list, because its considered Obsolete, and in the later game clicking on [SHOWOBSOLETE] means you might have a ton of items to sort though.