My son and his wife are so messy and unorganised

I really wouldn't put up with it. It's unbelievably rude and completely unacceptable. They're basically trashing your home and nobody has the right to do that.

The latest buzz word is "boundaries" and you need to set them. Your son, if not your DIL, wasn't brought up like it and he knows perfectly well it's not the way to behave.

I have a similar problem but the children are so much older so it’s not food or really dirty but it’s so messy, towels on the floor bags of stuff everywhere, undecorated rooms which have been started but not finished for years. The whole house is a mess inside and out. I don’t visit very often, usually arrange to meet up for coff somewhere or have a family meet up doing something like 10 pin bowling and they can always visit.

If you want to maintain a relationship, keep quiet about it. Their home, their choice. Your home is another matter. If you don’t like the mess, meet them somewhere else.

They won't appreciate you criticising their parenting skills or lack of but you are well within your rights to have your own rules and wishes in place when they visit your home.

I wouldn't like them visiting, its a very chaotic stressful way to parent. With grandchildren i would have to grin and bear it if I visited, however if they were not related I would not be visiting or inviting..If they visited me i would want them to sit and eat and wear nappies, if that's not possible just visit them,. Heaven help the teachers if one is five. Schools should not be expected to put up with untrained unruly children, it is pure laziness.

I think you have to fit in with them when you are in their home (their house;their rules). Some people are just chaotic by nature.
If you find it intolerable have only short visits or no visits.
By the same token however they have to respect your house (your house; your rules).
I think that allowing them to pee on your carpets(I find that incredible!) is intolerable.
I wouldn't allow anyone's dog to regularly pee on my carpets ( occasional accidents being different of course) let alone their children.

Easy: Your house, your rules. Their house, their rules.

Well you sound like such a supportive, welcoming granny

Totally relate here - my daughter and son-in-law are totally loving and devoted parents but unbelievably messy in their style. My daughter brings the kids up in a way that is totally different to the way she was brought up. But, the main thing is that the kids are loved and secure, the rest is just detail. Any attempt to intervene/comment will 100% be seen as attack on parenting skills and cause damage to your relationship. So not worth it, loved children is the most important thing here. Bite your tongue x

It's fine to have a mess in their home. So either put up or don't go round.

As for coming to yours, maybe just say you love to see them but nappies and bibs will be the order of the day.