That completely depends on the price.
If there's one game there that I want, and it's much cheaper to buy it as a bundle, even though I don't care about the rest, I will buy that bundle. What's the harm?

I actually buy a load of bundles. I bought almost every Indie Royale bundle when it existed. Often there wasn't much of anything interesting, but they had some music albums as bonuses, and often those alone made it worth the price. For instance, there was a brilliant album from Disasterpeace "Rise of the Obsidian Interstellar" which would make the bundle worth buying even if every game in it sucks.

These days I pre-purchase almost every Groupee bundle. I mean, it's only 1-2 dollars, and even though you don't know the bundle content at that point, there's not much to lose. Most of the time I think it's money well spent, and usually a part of that even goes to some charity purposes.

Bundles are almost a hobby of mine these days.

1 - depends on two factors:
---a) how much do I want the game(s) that I don't own already, and
---b) how much does the bundle cost.
If a bundle doesn't consist of at least one game that I don't own already and if that one game is not worth the bundle's price for me, then I won't purchase the bundle.

2 - see above: is that single game worth the bundle's price for me? - Then yes.

3 - already answered under 1 and 2: is the price acceptable for the # of games I'm interested in? - Then yes.

4 - no.

First: Do ANY of the items in it have DRM [AT ANY TIER]? I'm out. I'm not rewarding them with numbers to support DRM.
Then: Are any items those I already own? Rewrite the bundle as if it were only those I don't have...
Then: Do I have a likelihood to play any of the games in it that I don't already own? OK, probably get it at that tier.

This assumes reasonable pricing.

Pretty simple, really. I look at the games that interest me and judge whether they're worth the asking price to me, all combined. So depending on the total price and the games included, a bundle might be worth it to me for just one game I deem totally worth that price, or because it contains lots of games that I'm mildly interested in and that are very cheap if you divide the total price by their quantity. Sometimes I take into consideration if the games I don't want are likely to be wanted by someone else I know.

I reject a bundle if I have to buy it blindly, with the content not revealed to me, or if I'm not really interested in the games it contains, of course. Also, if I don't deem the games I'm interested in worth the total bundle price, because they usually go on sale for the same price or lower. I might also reject a bundle if it contains games locked in my region (but it's probably depending on the remaining games and overall price again), and I will most probably reject a bundle if it contains censored versions or forces translations on me instead of letting me play a game in its original language, or if it contains especially annoying forms of DRM or requirements for third-party accounts or platforms that I don't care for (SecuRom, Starforce, Telltale, Rockstar Social Club, consoles, mobile devices etc.).

I used to buy bundles jumping on what i perceived as a great sale thinking that those games i wasnt interested in I would give them a go and it was no loss. now my library is cluttered with games i have never even opened and have no desire to. and that perceived valute is shot to hell. Its caused me to look at my impulse buying and the result is that I only buy bundles if I like most of the games, even then I pause as I already have too many games to ever be able to finish them all

In a way, yes, at least if I wasn't 100% sure yet they wouldn't run on my system (e.g. Humble Monthly for Quantum Break), but it's not a common occurrence.

And recently, in addition to whether I perceive something as a good deal, I've come to take into consideration how likely I am to actually play through the games. I've grown used to buying a lot of games (cheap) just to try them, but by now (I hope) I've become a bit more realistic and reasonable in judging whether I'm really interested in playing them - even before I buy and try them.

Me, I think I'd actually prefer to buy the games individually (or wait on a better discount for them), and at one of my preferred stores (where I might still have wallet credit), rather than 'burden' me with a code for an extra game I have no use for. Unless that game is in very high demand with others, maybe (but it probably won't be for long, after it has appeared in a bundle).

The content obviously; i am OK for 4 games i want up to 25 euros, like the PS4 Kingdom Hearts 1.5 + 2.5 bundle... Often the Playstation humble bundle for usually full list at 15$.

Not OK for 7-8 indies for 2 to 3 euros because i will most likely never play them and just choke more my damn library... That is already filled by 2 to 3k of those over years of groupees + indie gala, etc...

Usually if it's a some sort of "Complete" bundle, of a franchise I wanted. I don't like cluttering by library with stuff I'm 99% certian I will never play.

Everything depends on the "game(s) that looks interesting or is wishlisted" to price ratio. If a game is wishlisted, it gains more points that if I just came across it on the bundle.

It probably has to have at 60% of interesting games... and ultimately, if I have enough money. :P

I've edited my OP to add new questions. You ALMOST sound as if you don't have a humongous backlog of games, that you could actually buy a game and play it soon after, even sometime this decade. Hehe, that can't POSSIBLY be true... Other people's opinions of games affect your decision? Not challenging, just asking. The only factor I use in determining whether I like a game is watching gameplay, like in a Let's Play. I long ago learned that what "the masses" think of something never has any bearing on what I'll think of it, video game or otherwise. Hmmm, sounds like a problem. You should probably come over and let me help you with that. Now, wouldn't you be more comfortable with your pants off...

This began affecting me a year ago. I even stopped claiming free games simply because I don't want yet another game out there I have to keep track of and that I'll almost certainly never play. Don't want the clutter. I'm poor so rejecting free things is... strange for me.

I've also become much more picky in bundles. I used to regularly check out indie bundles, but now they just seem like so much crap and too much clutter. If I haven't even gotten around to playing high quality games I own, why "burden" myself with a bunch of dross? I should digest what I own before biting off more.

The approach I'd take if a Humble Bundle I'm interested has a DRM-encumbered game (with no DRM-free version) is as follows:
* I would go no higher than the highest tier that has no DRM-encumbered games.
* When distributing funds to the developers, the developers of the DRM-encumbered game(s) get 0%.
* These days, as I no longer trust Humble Bundle (because of when they started putting DRM-encumbered games into bundles), the Humble Tip gets 0%. If possible, I give that portion of the tip to an organization like the Electronic Frontier Foundation that opposes DRM.

(Note: The subsystem of the Linux kernel called DRM is different (it doesn't even stand for the same thing), so it doesn't count as DRM.)
For me to buy a bundle blindly (or semi-blindly), I require that there be a promise that every game in the bundle is DRM-free. Also, unless a game that I really want has been revealed, I also require there to be a promise that every game in the bundle supports Linux.

Edit: I have yet to actually buy a bundle blindly. Humble Bundle started selling DRM-encumbered games before the Humble Monthly started, which was enough to make me not trust them for blind bundles.

More or less so, but it isn't the only criteria I have to be sold on the game (otherwise I would have PUBG, which means an install of Steam aaaaaaand...)

Basically if it's a situation like Undertale, I become more likely to want to get the game and see what all the fuss is about. This can help put the bundle into a better situation; but it's not exactly the "insta-buy" scenario.

An "insta-buy" scenario would be a bundle ticking all the boxes in my first post, and including a game I have an interest in getting. Which is hard to say as recently I haven't bothered to really pay all that much attention to games.

Humble Monthlies I judge based on what's visible. If the early reveals already justify the price for me on their own, I buy the bundle and take everything after as a bonus. If I don't think they're worth it, I don't expect the hidden games to be worth it either and just skip the bundle.

You are making an assumption that the total value of the hidden games is at least 0; as I consider DRM-encumbered games (as well as certain games that are particularly problematic for other reasons) to have negative values, this approach doesn't work for me. In other words, a hidden game can make the value of the bundle to me less than it would be without the game.

For example, if game B is DRM-encumbered, a bundle containing both A and B is less valuable to me than a "bundle" containing only game A.