@wh2 So, for starters, the pandemic helped me out here because nobody would just "stop by." So no longer did I feel the houses needed to be in a guest ready state.
My kids are 7.5 and 4.
The family all agrees that there are certain things that need to be done for the Household. But extra chores can be assigned for allowance money.
We just had a conversation at the dinner table about how if everyone does a little bit, then everyone has more time to spend together. That really helped them understand they why.
So our oldest helps with some chores, which helps, and everyone has to clean up after themselves.
They don't always (or often do it) but we keep trying to hold onto that value so that when they're perfectly capable to do so, the expectation they will is already engrained.
But practical tips is that everything has a home.
Ikea bins etc. Throw stuff in there and slide it to the side. I like things to be better organized than that but it's just not worth it with kids.
I also let them suffer with the loss of misplacing something cherished. The amount of times I respond with "well, this is why I tell you to put stuff back when you're done..." is mind boggling.
tl;dr: invest in some organizing things like bins and lower your expectations for what is acceptable and keep encouraging the practice of everyone picking up after themselves (while also lowering the expectations they will until they're much older).