In the hospitality industry of 2026, standard "business hours" for housekeeping to knock on occupied rooms are typically between 10:00 AM and 6:00 PM. Most high-end hotels instruct staff never to knock before 10:00 AM unless the guest has explicitly requested early service or "cleared" the room. If your "Do Not Disturb" (DND) sign is not displayed, a housekeeper will usually perform a "soft knock" around 11:00 AM to check if the room is available for mid-day cleaning. However, many modern hotels have moved toward a "service on request" model to improve privacy and sustainability; they may not knock at all unless you use the TV or app to request a refresh. If a housekeeper does knock while you are inside, it is standard etiquette for them to announce "Housekeeping!" twice before entering. If you prefer total privacy, always engage the electronic DND or hang the physical sign; in most jurisdictions, staff will not enter a DND room unless it has been engaged for more than 24 to 48 hours, at which point a "wellness check" by security may occur.