My middle daughter is a slob also. I let it go as long as I can, then finally insist she cleans. She does her own laundry. Which is about once a month or when I finally blow a gasket and make her do it. The main reason I make her clean is because I am terrified that the house will catch fire and they won't be able to get out of the room or I won't be able to get to them. But, as long as they keep a path to the bed, I'm usually ok.
(I was in a fire when I was a teen, so this is a serious phobia of mine)