Unless I misread the OP, none of the guests (all ten of them) chipped in with any cleanup or housework. It’s almost like they felt they were at an all-expense paid resort where food, lodging and housecleaning were part of the “package”. Either they were led to believe that or they were all just plain thoughtless.
Given that this is the case, the guests were especially obliged to clear up. If they’d supplied all the goods it might remove some of the burden, but even then a token gesture would have been polite.
For a dinner party, I wouldn’t expect anyone to offer to help clear up afterwards and in my house, any such offer would be refused. However, I think the situation is different if you’re there for a weekend and also if it includes a party of any sort. When we’ve been to parties at other people’s homes and spent the night there, we’ve always started clearing up in the morning and have made breakfast, done the dishes etc. Surely it would be more than rude not to?
When staying over at a friend’s house recently, I got a mock telling-off for doing her dishes, making cups of tea for everyone and doing breakfast butties. With other friends, it’s a case of making yourself at home - if you want a drink, you know where the kitchen is and you shouldn’t expect a friend to be waiting on you hand and foot.
No, guests are under no obligation to help out.
I say this from the point of view of someone who loves to cook and will often do all the cooking while staying with friends or relatives, even for days at a time.
Were your friends raised in a barn? If you’re an overnight guest, of course you should clean up after yourself and try to make yourself useful. They’re getting a free weekend at the beach, the least they can do is load the dishwasher.
Your fiance is right – guests should not be expected to help clean up. If they help, then lucky you, but you should not expect them to do so. Of course, keep in mind that I live in the South and was brought up with a sense of etiquette that many were not – a guest in my house is waited on, and not allowed to do for him/herself. I cannot imagine anything more gauche than expecting my guests to clean my house/dishes for me.
I have to agree with everyone else - weekend guests have no obligation to help out, but it’s pretty oafish to offer to do nothing at all, like you were staying in a hotel with maid service.
ETA: Nice juxtaposition there, Litoris. 
Kayeby, I might not have offered either, because it’s only one or two very close friends who’ll let me do it (and even then, not always) without huge shows of, “No no, you sit down. It’s ok!”
So they didn’t do the wrong thing, and you were right not to resent it. The best thing you can do for the great global karma of visiting friends is to accept help when it’s offered. Hopefully, that will be playing your own small part in making things easier for everyone (coz I really hate the ritual of offering and being denied - not that you did that).
No, but they should offer. If it’s a casual weekend, you can accept, but if it’s a formal dinner, you should decline.
In general I’m of the group that says the guests don’t have an obligation, but that they usually do wind up helping somewhat. Part of this is how the host subtly manages expectations.
I don’t think this helped matters. It set the tone that it was OK to eat breakfast with the house in a state of squalor, and that guests would be fending for themselves for breakfast. Also, expecting them to start cleaning in your absence is unlikely. I think you would have gotten better results if you’d been up first, gently setting the tone that debris needed to be cleared before breakfast was served.
Also, I don’t see why they’d be expected to make the beds. The beds need fresh sheets, so what’s the point? I guess maybe you wanted the comforters to look nice so you didn’t have to replace the sheets right away? But that’s not obvious to the guests.
I go with this too.
As a guest, I especially would clean up after myself in the case of making myself breakfast and dirtying pots, pans, and plates. As a host I would not expect my guests to clean, but I would certainly be impressed and appreciate the thoughtfulness and courtesy if they did. ETA: Although I’d probably tell them to stop, because they are guests.
I think it would be nice for guest to offer to clean up, but it shouldn’t be an expectation. I agree that being the last couple up probably wasn’t a good move as hosts. If it had been me, I would have been first up and started tidying then. That way guests can see that tidying is required, and if they offered, I’d allocate them tasks to do.
I don’t see an issue with the beds though, you need to change the sheets and remake the bed so it really doesn’t matter what state the comforter is left in.
Being last up was bad host behaviour but I would never be a guest and not at least offer to help clean up.
I was bought up to believe that it was rude not to help to the dishes when invited for dinner. I had very mean parents
Do they have an obligation - no. But if they ever want to be invited back, they should pitch in.
Overnight guests are different than dinner or day guests. And weekend or several day guests are different still. If you have servant paid to pick up after yourself and your guests, its a little different, but few of us have a household staff to do our dishes for us.
Anyone who doesn’t pitch in and lets their host clean up after ten people for an entire weekend is inconsiderate.
I WOULD express my irritation to my friends - next year when they say “that was such a nice weekend, could we do that again” I’d respond with “oh, that was so much work, seemed like I spent the whole weekend doing dishes and didn’t have a chance to enjoy anyone’s company. Next time we all go for a weekend, lets go to a resort where I can enjoy myself, too.”
When we go to a friends lake house, we all pitch in Sunday before we leave. Every bed in the place gets washed. Dishes are all done. The house gets vaccuumed and dusted, the bathrooms get cleaned. It takes the eight of us (four adults, four kids) a very busy morning to get everything done before we pack out.
To me, if they feel comfortable enough to make breakfast, they’ve blurred the “guest” barrier and they should be obligated to clean. If nothing else, I can’t imagine dirtying the kitchen by making breakfast and not cleaning it up; that’s just flat out rude.
I agree.
As a guest, I offer to set tables, clear tables, stack the dishwasher etc.
As a host, I try to do it all myself, but thank people who help.
I can’t imagine being a guest at someone’s house for a weekend and not doing basic things like cleaning up the kitchen, throwing out trash and making the beds.
It’s not even about “I’m going to clean the kitchen so they invite me back next time”, it’s about showing respect and thanks to my generous friends.
Plus, I could never cook breakfast in a dirty kitchen! I would have to at least load the dishes from the previous night before I make the coffee or get things packed up for the beach.
Kids these days!! 
I see a difference between ‘housework’ (stripping the bed, changing linens, doing trash, washing dishes) which a really good guest would help with, and cleaning up after oneself (throwing away trash like plastic cups, rinsing dishes, keeping the place relatively tidy) which anyone should do.
It sounds to me like you’re a really good guest and your friends are really really bad ones.
(For the record, I’m 26 and I always make the bed and clean up the kitchen when I’m staying with friends/family. The longer I’m there the more I do)
It depends on the situation, but in general, guests shouldn’t be expected to help out. Of course, if a guest doesn’t help out, it’s expected that when they invite you over, you shouldn’t have to do anything either, and in that way it’s fair. Of course it depends on the relationship too - are they family, especially family who used to live there? In that case they might be expected to help out in whatever manner they used to be.
I agree that if the guests are comfortable enough to make breakfast, they should be comfortable enough to clean up after it. And in general, if the guest “makes a mess” they should clean up after it - wipe up urine if they pee on the seat, put something back where they found it, etc. I wouldn’t include cleaning up after dinner, because they weren’t involved in creating the dinner and the dinner is considered a gift to the guests. I think it’s ok to ask guest children to help host children with their dinner related tasks. I definitely wouldn’t ask the guests to do something that’s not directly involved with their activity - they shouldn’t have to rake leaves or anything.
It’s polite for guests to ask if there’s any way to help out, but I wouldn’t just start doing something without asking. The host may want to do everything as part of the experience of hosting, or they may have a certain way they like things to be done when it comes to cleaning up.
It’s a different situation if the guests are staying for a prolonged amount of time, or if they are meeting the technical host in a place other than the host’s own home (like a time share).
How very well-mannered of you to say so.
I’m actually not sure why this bothered me so much. Although it also bothered my fiance a little, when the other things didn’t annoy him. FYI a visual reference taken from Google pics:
This is how I left the bed
This is how they left the bed (only without the crap around it)
I just found it visually jarring - personally I have never left my bed like that at someone else’s house. Everyone had already left, we were doing the final tidying, I was having a bit of a private pity-session, and I walked into their rooms and just thought … for fuck’s sake …