Depends on how big it is; if it's less than a gigabyte, I usually don't bother uninstalling unless it's one I really dislike.

If it's over 5 gigabytes, I always uninstall it unless I expect to play it within the next month- with the exception of StarCraft II, which I just keep installed all the time.

With TB hard drives having dropped so rapidly in price over the last couple years space should never really be a concern anymore, for every 1 TB i buy I buy a second to act as the firsts backup lol.

As for choosing if im not focusing on a particular game or series, I have is a shortcut on my taskbar to a folder that is filled with shortcuts to well over 500 games, so I kinda just spin my mouse wheel back and forth like mad and then click on something at random, or the other one is use a couple d20/d100 and assign genres to a number and work a game that way :p


Happens far more often than should be allowed lol

I only have 700 gigs of space on this rig (410 on D:). If a game is a DRM-free, and I have no intention to re-play it in the near future then I will un-install it.

Any games from Steam, or Origin, old disc locked DRM infested, or games I’ve had to patch significantly, I back up onto an external 2TB HD, and then manually delete most of the files, leaving only the main folder(s), small files and .exe to free up space. That way I don’t have to worry about limited activations or having to re-install (or patch) the game, I just copy over the files whenever I feel like playing that particular game.

Every GoG game I buy, I install it and at least play the tutorial or beginning to test it, and then un-install, so I don’t have too much pressure of a pressing backlog of games to get to, focusing only on those I want to play all the way through, in the moment. :)

Put me in the "delete" camp too. I also delete all my saves :).

When I get a new game I also download it to test it out. Then I keep it on my hard drive until I'm ready to play it. However, recently my hard drive was getting full so I had started deleting some of the the unplayed games I was saving. It's not a big deal for me to redownload them later, although I have a download cap on my internet (125GB per month) I'm always well below the max anyway.

I keep a list of all my games in a database though so I don't forget what I own and where I own them.

Usually I uninstall because when I'm done with a game even if I can go back and do some additional content.. it just feels kind of unfulfilling.
Sleeping Dogs for example has some of the (IMO) worst side activities ever, so going back immediately upon finishing it did not hold any appeal to me. Now I kind of feel like it, but them releasing a remake and not having a previous owner incentive kind of ticks me off.
New Vegas on the other hand I played three times in succession due to the different paths and 'builds' you could take.
But usually when I'm done, I'm done.

The first game that get's installed after every single configuration change/OS reinstall isWorms World Party.
Newly added (yeah I have a strange sense for the word "new") ones Sid Meier's Civilization V & Worms Ultimate Mayhem looks like they will have the same faith as the one mentioned above.

Some game series like The Elder Scrolls and Football Manager that require much more time to be finished don't get uninstalled because I play them in "every-few-months-sessions".

And there are always some small games like Pac-Man, Icy Tower, Retro River Raid that I have installed if I need something for a few-minutes play, but honestly I rarely play them.

Other then that I usually uninstall a game after I finish it.

There are games and games. Sometimes you finish and it doesn't add nothing, sometimes you finish but there's something to go back.
Examples:

I've finished Just Cause 2 recently and kept it installed just because sometimes I want to numb myself from the world exploding things, and MAYBE one day I'll achieve 100% completion (finished with 26%, currently on 28%)

But there are games like Lost Planet:Extreme Condition where after finishing it I was like: "Why the F did I buy this"? DELETE.

Its become impossible due to library size to keep everything installed. Ideally, I would like to keep it all installed. This is further exacerbated by all the scratch space I need to archive my movies, photos, music, and game patches, etc.

I have my favorites that I try to always keep installed, but its even becoming more difficult to justify those if I want to try too many newer games (which are clocking in at dozens of GB each.

For now, Thief 1, Thief 2, Thief 3, Thief 4, Morrowind, Oblivion, Deus Ex 1, Vampire Bloodlines, and Painkiller all get priority space on my HD after a new install (always). Then I have to juggle around what I want to play next. Even though storage is getting very cheap, software sizes aren't getting any smaller :/

Uninstall usually. My windows partition is just 100 GB, with games like Dragon Age taking up a fourth of it i don't really have a choice ;)
Mac games i usually keep installed somewhat longer, mainly because most of them are a bit older or installed using Wineskin (although i usually save the Wrappers without games anyway) ... and my OS X partitions are 4TB, so theres more room for nostalgia.

If it has a cloud save, then I uninstall. If it doesn't, then I debate with myself for a little while to either keep or not keep the save files. Then I uninstall.

It depends. In case of a GOG game, I immediately uninstall it without deleting the saves: after all, I keep all the installers in a separate HDD, so re-installing it in case I wanted to give it another go would be a matter of seconds, minutes at worst.
Same goes for the backup of other DRM free games I have, even if they are very few outside this site.

If there is a game I play every now and then (mainly if it is among the "endless" ones, see Alpha Centauri, for example), there is no reason to remove it.

If it is one of the "big" games that require a certain client to install and I don't have a DVD (or the gigabytes and gigabytes of patches make it worthless), though... well, that sucks! :P
Luckily for me I stopped using those (both for my ever-increasing anti-DRM stance and the fact that, frankly, the vast majority of AAA games do not attract me in the slightest anymore. I could say that since the beginning of the "last generation" of games I liked only Hitman: Blood Money, Overlord, Dishonored and New Vegas among the tens of titles I played), so now I don't have the problem... before this, though, I used to keep the games until I ran out of space -my awful internet connection played a maor part in this- then progressively deleted them based on how many space I needed and what I thought I would have played again.

I have all software installers backuped on external hard-drvies. If needed, I can quickly reinstall everything. If I feel I'm done with a game, which means I will not play it n the near future, I backup my savegames and uninstall it. I hate it to have unnecessary stuff installed. Exceptions are maybe troublemakers, programs that are hard to configure, but as far as I can remember right now I don't have such programs or game installed. Keep it simple and clean.

It depends on a lot of things. If the game is replayable or have harder modes, secrets, minigames, unlockables, etc... I consider not uninstalling it. If its light, I dont mind having it installed in my HDD. But otherwise, if I´m looking forward to install a heavy new game and I want to install it asap, I free disk space uninstalling games I dont usually play or games I´ve finished.
And if I didnt uninstall a game to play more in the future and I dont play it in a long time (like some weeks), then I uninstall it cuase its useless there.
As a mate said up here, if its a GoG game and I have the installer in my computer (so I dont have to redownload it again in the future) I would uninstall it almost instantly if Im not aiming to replay it soon.

It depends on the game. I have some games which I always keep because I (re)play them regularly or they have multiplayer. and I play them with friends. I mostly uninstall games right away if I need space on my HDD or if I didn't like it that much.