My experience with this was about 2 years ago, SD was 8.
SD said "I don't want to live/visit DH anymore because you make me clean my room, make my bed and empty the dishwasher and BM doesnt"
Our kids get paid for chores, 1.00 a chore, so I let DH handle that moment and I never asked her to empty the dishwasher for 2 weeks, at which point she went crying to DH that she "isn't going to make any money because DD does it all now"
So we started assigning her chores again, BUT now she just refuses, and has even gone after DD and hit scratched her up because DD was doing chores SD refused to do.
I just assign it to DD now and pay her, DH doesn't make SD help out anymore either.
Its better to just avoid the chore drama in our house, SD calls the shots on that and I don't care anymore

I am afraid if you don't have DH's support, you won't get far on this (ie. nowhere). You are absolute right of course that SS should do chores. He should do the chores you tell him to do because he is living in your house...fair or not shouldn't even be part of the discussion. But in reality, if DH sides with SS, forget it. You are already the outsider even if it wasn't 2 against 1. My SS17 won't do a damn thing even though we have 50/50. In case you think I am exaggerating, I have been fighting for years to have him get the mail (10 steps from the front door) just so he has some minimal involvement in the house. This started when he was 8 when getting the mail seemed to be an age appropriate introduction to chores. Forget introduction, I never made progress. My husband has defended his laziness as if I was asking the kid to jump in front of a firing squad. No he can't possibly get the mail. Its too cold. Its too hot. Its dark out. He's too tired. Whatever. I gave up. Husband runs for the mail now so I don't ask SS. I spend my days now counting the days until college. I am not responsible for the kind of human that was created under my roof. I tried.

Both my bio's lived with us full time, SD's lived with us 50% of the time. The deal was when SD's weren't there chores were to be done by bio's, when SD's were there chores were to be done by them
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See...not so sure this is a good thing. The skids (part timers) had the same about of chores as your kids. (full timers). That does not seem fair to me.

I am a total believer that EOWE kids should not have chores. I mean, they can cleanup after themselves but as far as heavy chores like dusting, sweeping, mopping, cleaning bathrooms...that is for full time kids and adults.

My SD had to clean her room and vacuum it before she left on her weekends, basically, leave it as it was when she came. I didn't consider that a "chore", just picking up after herself.

Vacuuming the space where your SS stays when there, is not that big of a deal. Surely, your son does more if he is there 50% of the time? How does your DH figure that his son does as much as yours?

I think they are fair.. The only real chores we have currently are making sure they pick up after themselves. Like picking up toys and clearing the table after they're done eating. The oldest child in this house is only 8 though so when they get a bit older we'll start making them do more.

Leaving all that up to the full-time kids and adults sets a nasty precedent
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And so does having a kid there 4 days a month, cleaning up after all the full timers. Actually...that is a servant.

I still think that 4 day a month kids should really just have to clean up after themselves and their rooms. (if they are allowed to have a room at dads house)

OP...Make DH vacuum it if you feel that strongly that his kid should do it.

We will have to agree to disagree.

Kid should have a couple of chores - pick up stuff or set table wen he is there
A little responsibility is fair
I agree if dh is against him do vaccum then dh does it
Also dh needs a head check : either kid is part of family and helps out with that enforced or kid is guest and not part family. CANT HAVE BOTH WAYS

4 overnights a month and dinner (guessing 2 hours twice a week). 40 percent??

Now if it were actually 40 percent, I could see that kids chores should be about equal. But I don't see this as 40 percent at all.

I guess it's how you choose to view your relationship with the kids. Do they spring into existence in your life during the 10%-20%-50% custody time that you have with them and fade away into the wallpaper when your time together is over? In that case, you should treat them as hallowed guests, or, at a maximum, give them a few token responsibilities so that they don't *create* more work for you during their EOWE appearances - reducing the skid 'footprint,' so to speak.

Otherwise, give them normal responsibilities for the time that they are there. Of course they can't do daily chores, since they aren't there daily. But they can do their share of those chores when they are there, and contribute the (step)family unit with weekly and monthly responsibilities as well. Responsibility fosters independence and belonging.

The rule in my house is this.
"If you are in my house,you are responsible to help maintain this house."

SD14 is only here a handful of times throughout the year-she still has chores to do...like it or not.
If my nephews or niece are here-and they make a mess...guess what-THEY CLEAN IT UP.

I make the rules crystal clear to anybody who walks in my door.
I will be the sweetest hostess you'll ever meet...but treat my house like a pigpen and you'll get treated like Cinderella real quick.