I worked out that the reason the place gets in a state is that DP hasn't mastered the practice of Cleaning Up As You Go.
When we cook together or I cook, he gets confused by how much cleaner the kitchen is - that's because I'm scooting around, wiping up spills, chucking packets and peelings in bins, putting ingredients back and washing bits up as I go, so all that needs to be done afterwards is wipe over the hob, take the plates back after eating, scrape them off and wash up a couple of things, plus quickly run the sweep over the floor to pick up anything that's hit the floor. He doesn't even notice I'm doing it.
My clothes get dropped in the linen bins as they leave my body. His get left on the floor until it's time to do a washload.
If I see a spillage, I wipe it up there and then. I came in from work today and whilst we were talking, I spotted something on top of the washing machine, so squirted it and wiped it up midsentence.
When I'm in the bathroom, if I see his contact lens packets on the shelf, they go in the bin. The towel on the floor gets picked up, the loo gets a quick wipeover if it looks dusty and I'll swish over the sink as I'm washing my hands. It takes seconds.
Even when it comes to tea, there's a difference. He'll get a fresh mug out of the cupboard and bring it over, I'll take the previous mug back into the kitchen, rinse it and use the same one again.
Leaving cleaning until it's a huge job is just a waste of time and energy - I've left it to him quite a bit whilst I've been working and he wasn't - after a while, my Saturday mornings consisted of ragecleaning because I couldn't even find a mug to have a cuppa, as he'd allowed things to build up.
However, now, he seems to be getting the idea. It's largely immaculate - I will still clean on Saturday morning, but it's more the non standard jobs and lots of sitting down in between bursts of activity, not the day to day keeping on top of things or slogging for hours on muck and clutter. I don't mind doing it - I hate a home that looks grubby and cluttered. And he's less likely to put off dealing with anything because he's seeing how much easier it is to work with a good basic level of organisation.