They’re an indispensable tool of the trade for hotels. Travelers depend on them for an uninterrupted night’s sleep. They let staff know how best to serve guests. Yet you may never have thought of using door hangers for your business.

Think about it: a simple door hanger sign tells hotel staff, “Do not disturb!” or “Please clean room.” It’s one of the most effective means of communicating, and doesn’t require any technology whatsoever.