Do you sell XBOX 360 games after you have got the Achievements?

Do you just complete games to get the Achievements and then either let them collect dust amongst your collection and never play them for some time, or sell them?
 
I sold 3 games back to gamestop last week just because i got the Full 1000 gamer-points. 
 
So will you hang onto your games to play them again after you have got all the Achievements or sell them? It may be because it has a great online like Call of Duty 4, GTA4 or whatnot.
What do you do?

No, I like to keep a "collection" - I think I have over 100 Xbox 360 games now.

I only sell a game if I didn't like it, and if I got 1000 achievement points in it, I probably liked it.

Never.
 
Plus what is the point of selling games after achievements? I never understood that concept of achievement hunting. It always looked like a weird way to extend the life of some games, or to make other games playable/marketable, like that crappy Avatar game.

I never sell a game. even if the game is awful, i'll keep it in my collection. 

" I never sell a game. even if the game is awful, i'll keep it in my collection.  "

" @AjayRaz said:

" I never sell a game. even if the game is awful, i'll keep it in my collection.  "

This. "

I can't stand  achievements I think they are a total waste of time unless it is needed to be done as part of the game!  Otherwise I don't get rid of my games unless I just can't see myself playing them any time soon