My brother and me do this all the time. In Half-Life I mostly used the self-recharging (but weak and slow) Alien weapon, saving my stronger weapons for when I needed them. I mostly used the pistol to kill off the boss.
In World of Warcraft (which we both quit months ago [yay!]) we had heaps of equipment for possible future alts. Our bags were also always full with crap that might one day come in handy. With pain in my heart I had to disenchant my tier 0 and tier 1...
I beated most of Myth II with tactics instead of some of the main characters powerfull spells.
In TES:Morrowind I had a huuuuuge collection of candles in 'my' house. It must have been more than a hundred. I had to collect sómething. The rest went to the vendor. Oh except when I started to collect the different armor sets.
Lately I've been playing games less seriously, that helps.
Original thread:
http://www.eurogamer.net/forum_threa...hread_id=82808