Luigi actually stays in his mansion. After one night of making sure there's no ghost he's stays there. He doesn't stay in a castle like Mario does because he has no purpose to. He doesn't ask to stay in one either because he's a gentlemen(not the Mario isn't don't scream at me). So far he has the most commonly used areas that are clean but the others are still pretty dusty.
YOU ARE READING
My cartoon and video game theories
AléatoireThis is my book of theories on a base of lots of things like Sonic, Mario bros, Tmnt, etc.