One of the classic issues that can come up in a game is the Monty Hall syndrome. Basically the party collects SO many rewards and gear they don't need anymore. Or if they find a new item it gets thrown in the pile never to be used, or to later quickly be turned into money. (For those rare few that don't know what Monty Hall refers too, it's a call back to the Let's Make A Deal gameshow. Implying that the players can trade prizes for greater rewards and goodies if they take what's behind door # 2, etc.)
My solution to this issue originally was to use a different system than D&D (where the problem originated from). Which for the most part worked because games like GURPS and HERO had way different power economies that relied more on the players creativity to use their points and background bonuses to meet the needs of the game. 4E D&D tried to fix it by enforcing itemization at a balanced rate, but later recanted in the DMG 2 and offered non-item stat rewards that did more or less the same.
In the end the problem came down to an imbalance in raw utility of the items vs the need in the universe. Once you hit a point of diminishing returns on things like raw +1s and movement items what's the point? It's just window dressing then. You overpower your foe and move on.
Which is when I hit upon the solution to my problem. I need to tackle itemization like Iron Chef.
Yep. The idea is pretty simple. You give the players raw material. Now I'm expressly NOT talking about 4E's residium nonsense, that's to easy. You need to give them in D&D terms masterwork raw materials and quests and optional goals to find the enchantments to power up the items. This is not to dissimilar to how GURPS or other enchantment systems work. The potential for the upgrade is there with the character, but unlike them finding random items that may or may not fit their theme (and most players have a theme for their character) you give them the direction the must go to customize. So like Iron Chef, you get an ingredient and the tools to make what you want, but have to adapt to what the ingredients is each day.
It's like you find a chest full of adamantium ingots. No one locally can forge them for you, but you hear of a smith in the capital...and it just so happens to be near where your contact is waiting. Or maybe you find scrolls with spells, and a blank book to scribe them into. Etc, etc. This also works in non-D&D games. Like finding fuel rods, or weapons kits to upgrade you weapons later.
The trick is every once and a while something complete needs to show up. This adds that zest of randomness to the game and makes it NOT feel like Planet Ikea.
That said, this runs into problems if the players don't have the skill to know what they are finding. Appraise and Craft skills are very useful in these kinds of games so make sure warn the players. There is nothing more frustrating than picking up random materials and not knowing what to do with them.
This can get a little out of hand though. In some games where salvage from monsters and broken items becomes useful players will go skinning EVERY dragon they slay, they'll rip the bark off trees, and generally go around harvesting the world like klepto-locusts. But hey, if they are having fun, let them do it.
It gets even better if you give them possible options for item creation from the raw materials they are collecting. Bat wings mixed with the ruby of Yarl, and the strange sky metal rod might make a wand that drains health, etc. Be creative and have fun giving them 'discovered' recipes. Half the fun as a GM at that point will be coming up with strange item mixes!
Now if you'll pardon me. That apple looks delicious!