I used to work in that type of environment also and I agree with you with regards to the mess
I think it was mainly as they knew the property wasn't theirs but sadly when many moved on they kept their homes just as dirty
BUT we are not all like that I keep my house lovely and clean I am bit messy but I call it being creative plus I have no one to answer too!
Main thing I watched out for was used needles and wore those massive gloves to pick stuff up with used to take ages health and saftey and all that