Housekeeping is a labor-intensive job. They do not *expect* tips, but I think they certainly do appreciate them. We don't have tons of disposable income, but I always leave a little bit-- $4 or $5 a day--as a thank you for cleaning up my kids' and my mess. Occasionally there's a day I have no small bills on me or we rush out to the park and I forget to leave a tip, but I make sure to remember the next day. Sometimes I feel like the guy who rushes out to my uber car to open the door for me expects a tip, and I feel odd about that--I can open my own door--but housekeeping is genuinely tiring and sometimes gross work.