I'm a messy person myself but there's a point where things get TOO messy and you can't let it go.

I don't have a huge problem getting my 9yo to clean her own room as long as it doesn't get too ridiculous. She used to do the shove stuff in anywhere trick as well because she was getting overwhelmed. Get in there with her and tell/show her how to do it and where things go works pretty well, the little ones seem to like direction and don't like being forced to do a huge job, they like smaller jobs better so break it down for them.

The toddler trashes the lounge though and she's too young yet to convince her to put stuff away. The bigger one gets paid to do that but is inordinately slow because she has to sort everything by colour and line it up by size first instead of just picking up all the books and putting them away and repeating for each type of toy in the lounge. She has several other small non-essential jobs she can do - her idea to do them - so if she doesn't do them they don't get done. Her current bribe for doing it is to build up some money to buy lego with.

I don't let the big one eat in the lounge but the small one is allowed otherwise she screams the house down and won't eat at all so we give in for our own sanity. We're moving house soon to a more modern floorplan where the kitchen/lounge/dining are all in one room so it might not be such an issue there, and moving is a good time to start new habits anyway.