If you’ve been looking for more great ways to be even greener, and you already drive a Prius, carpool, use those spiral looking light bulbs, recycle everything, have a composte pile and purchase carbon credits, this may be just the thing for you. Please consider using your bath towel multiple times before washing it. Hotels are already beginning to encourage patrons to do just this. Many chains request that you use your towel at least twice, but if it needs laundered, just leave it on the floor.
Now this is an absolutely necessary and critical component to this incredibly environmentally friendly energy conservation measure: Always, and I mean always, keep track of which side of the towel you use for your face and which side you use for your nether regions. Obviously your towel only touches your body when its the cleanest, but even so, its just kinda gross to think about what might happen if you’re not paying attention. Feel free to use my patent pending solution: Tag side of the towel for face and body, opposite side for the unmentionables.
So to sum up: 1. Save money. 2. Save the planet. 3. Avoid cross contamination.
Do you use your towel more than once?
Song Of Sloman 
Yes, I do use my towel multiple times. I hang my towel on a hook "face" side up so I always know. Great thoughts. I miss these random conversations.
My towels stick around for a week or so. However, I find hotel chains just put that sign up to make you feel good about staying there because they are trying to save the planet. When in reality the maid changes out all the towels every time he or she comes into the room. I can’t remember a time when a used towel stayed in my hotel room when it was cleaned.