With rare exception, I keep games. Now I have a pile of games collecting dust, and am enjoying the odd satisfaction of playing digital PS+ games that aren't mine to keep. The idea that I can delete a game, but at any point download it and play as long as I like, then delete it again, is kinda nice. Phywical copies have their own obvious benefits, but storing them can be a bitch.

I keep them all

I keep most of them.

Exception 1: they are bad and I can still sell them for more than 10 € (less than that: not worth the effort of selling)

Exception 2: they are really, really bad and I want them gone forever... then I give them away or throw them away

Exception 3: I replace them with a better version of the game

• I sold most of my PS2 games when HD-versions for PS3/Vita were announced (Jak Trilogy, Sly Trilogy, Ratchet Trilogy, MGS 2+3, GoW 1+2, Final Fantasy X/X-2...); many of them even got cross-buy for PS3 + Vita
• I sold most of my Xbox + 360 games for better PC versions (Jade Empire, Fable, Sudeki, Oddworld: Stranger's Wrath, Condemned, Gears of War, Tomb Raider: Legend, Lost Planet, Mass Effect, GTA 4, Resident Evil 5, Alan Wake, Brütal Legend...)
• I sold The Last of Us instantly when the remastered edition was announced... luckily before buying "The Left Behind" for PS3
• I sold my PC-version of Grim Fandango when the remastered edition was announced... huge control improvements, especially on Vita
• I replaced some standard versions with "complete editions" which included all DLCs

Exception 4: A huge price difference between my old retail version and an identical or better digital version:

• I sold my GC-version of Wind Waker for over 40 € and got Wind Waker HD for free (bonus game for early MK8-buyers)
• I sold my N64-version of DK64 + Expansion Pak for over 40 € and got the WiiU-download for 10 € instead
• I sold my Wii-version of Metroid Prime Trilogy and got the WiiU-download for 10 € instead
• I sold my PC-versions of Final Fantasy 7 + 8 for 120 € when the handheld-compatible PSN-versions were announced for $10 each
• I sold many retail PS3-games and some Vita-games when the download versions were added to my Instant Game Collection

I usually keep my games.

Since I don't have much time time to play anymore, by the time I want to get rid of a game, it is usually worth next to nothing (and not worth selling).

I have traded-in some games when a GOTY or remastered version was announced (LBP, Last of Us, etc).

I used to sell back, but I bucked that trend in early 2007. Quite glad I did.

I sold all of my games and consoles years back(17 years ago) when I got married. I have been slowly getting them all back again. The only difference is that I only buy the old games that I liked the most. No need to buy every game that I have played...

Always! Even shit ones like Beijing 2008!

I did keep them all in the past, until i realized that i rarely ever go back and play them. Now i keep very few of them, seeing you're usually better off to get rid of it, and rebuy it in a few months, when it's $20 or less.

yes.. otherwise I don't remember which games i actually have.. well actually i still can't remember and accidently buy the same game twice from time to time..

I sell only those I know I won't play again.