Now, when you purchase a house. your house will be clean and tidy.
As you and other's enter your house, there's a chance that your house will get more dutiful, there is a higher chance if the owner him(her)self enters the house. It has a lesser chance for visitors (invited, house unlocked) and a more meduim chance for users with house keys.
Trash will not increase while law enforcement enters your house while a wanted criminal is inside.
Now, as for fires, this will be the 3rd type of fire on the server.
Normal spreaded fires, vehicle fires, and of course house fires (now store fires added).
House fires have a pure randomness just like the car fires.