Normally I keep every game I buy and every console I buy. Got 2 boxes of assorted N64, Gameboy, PS2, Gamecube and PC games in the attic just in case I want to play them again.
I have only ever traded in/sold 3 games and 2 consoles. I sold Age of Empires 2 expansion and Age of Mythology to a friend as he wanted them and I'd finished playing them (I then bought them on budget about a year later), I sold my GC (no games or controllers) to a friend after I'd bought a Wii, I gave my Gameboy Advanced to my (then) Girlfriend after I bought an SP and I traded in Street fighter IV after 5 hours and 5 holes in the wall. They build those Xbox 360 controlars like brinks and I remembered why I dont have any serious fighting games in my collection.