Here’s the thing: unless you specify otherwise, the default for most hotels is to wash your linens and towels every day. Think of how many rooms are in a single hotel, then how many hotels are around the world, and you’ve got a lot of water waste from unnecessary washing. Thankfully, many hotels have put policies in place to reduce the amount of laundry going through their system; generally, hanging a towel back on the rack means that you plan to re-use it. As well, there may be a card provided for you to leave out if you’d like your sheets to be changed. If you’re not sure, ask at the front desk about washing policies. Or, if in doubt, you could always just leave up your “Do Not Disturb” sign—sure, it means your room won’t be scrubbed down that afternoon, but are you really such a messy guest that you need a daily sweep?