I have seen plenty of rooms in these states, as a social worker I used to work with the hospital, ensuring that people were safe to go home, and that they had appropriate support when discharged from home.
Some of the homes I saw were absolutely rank, the worst being were there was about 20 cats, each room was filled with garbage, cat's muck, and rotting cat food all over the place, rat droppings. I could only get into the house through a corridor which was narrowed to about a foot wide, and each room you could only enter about two foot into the room.
He lived in one room, where his bed was, and a small little camp burner to cook on, the sheets looked liked they hadn't been washed for about 5 years, stained in feaces and other unnamely stains, the smell just made me want to vomit from the start.