What do you do with bundle keys?

Activate them immediately, trade for other games, some people give them away here

Let it there, feels safer imo

I believe it's better to redeem to avoid any keys being revoked or cancelled.

I've always let them there (HB, Groupees, Bundle stars) and never had any issue.

If u want collect games = activate them or/and drop cards if u want some few cents back
If u want some another games = trade them
If u dont need them = giveaway

Its not important if it months, i found acc on groupess and some bundle inside after soem months and all works well.

ur supposed to rearrange the letters and numbers of the key so it comes out as a sentence

I instantly get the keys to keep them elsewhere. Otherwise I would get really confused as to which bundle has keys remaining etc. and have to load the bundle pages (some of them which are really slow like IG).

I'm using an Excel document (or to be exact, I'm using the free version from open office) to catalogue all my unredeemed game keys until I need them for a trade or giveaway. I'm buying a lot bundles from different sites. I would not be able to remember all my unredeemed games and the shops where I have bought them. And if someone is asking me for a trade I just have to open the document and can tell him / her if I have the game he / she wants :)

If you reveal all your keys instantly, you have to be careful keeping records, so you don't forget you already used one. :) If you don't reveal the keys, you can always see which ones are safe to gift/trade/whatever.

But there's one extra thing to remember - sometimes bundle sites die. I have a pile of keys locked away somewhere at the remains of Indie Royale, OneMoreBundle et al. that I'll never be able to use, since I didn't reveal them. :(

steam_keys.txt
usedsteamkeys.txt

It depends on the site. Sites where finding unused keys are easy (humble, groupees) are sites I'll keep the key on. Sites where it's not, I'll grab the key and put it in a text document for future use.

What SketCZ said above is the best answer in my opinion.

In addition, I would recommend to use a spreadsheet to maintain the keys, and to back it up regularly.

Thanks everyone. Wasn't expecting such a 50/50 answer. Personal preference i guess.
Will take on board what you all suggested

Humble, Groupees, BundleStars, DailyIndieGame, and IndieGameStand all seem to be entirely reliable in storing your games/keys, and Humble has a solid reputation for fixing issues as best they're able.

Meanwhile, IndieGala is unreliable in many respects [and if you don't immediately store your keys off-site, you run the risk of losing them all if you're one of the small handful of users that IndieGala randomly deletes the account on (as I was)], while GreenManGaming actually has an active policy where they outright drop support for any purchases a week after you made them, so it's critical you test those keys to see if they're working immediately. If you wait too long, they've been known to invalidate keys.

In summary:
You're fine storing on-site for most sites (basically, any site other than IG and GMG and less-well-known bundle sites should typically be safe)- however, it's basically always a good idea to backup games and keys whenever possible, just to be safe: So if you've the energy to put in the effort, there's really no benefit to storing them online across numerous different sites, each of which has the potential to have an issue eventually.