Obviously every property is going to have rules that must be enforced. Every owner is going to need to document these in a rental agreement that a guest signs. And there are going to be some notices that just need to be up in the property. But if you care about making your guests feel welcome, try and keep notices to a minimum, and find a friendly way to express the ones you have to put up. One way to rationalize putting up fewer signs is to ask yourself - "will the person that is likely to do this wrong really pay attention to the sign?" If not, then you're really just irritating your well behaved guests for no gain.
The one notice we have up at both vacation properties is a framed set of information with the condo address, our contact information, emergency numbers, and key rental and association rules. These also include some of the things we include in our check-out checklist. We try and make these friendly, such as: "Please take just the sheets & pillow cases off the beds and pile them on the bedroom floors, so our cleaner can quickly find all the linens that need to be washed. (She's a hard-working woman, so please let's not make her hunt for the laundry!)"
One other notice we have in our Beech Mountain Bliss condo is on the dishwasher. A combination of the type of water on the mountain, and a very basic dishwasher, means that using a little less dishwasher detergent is important to avoid residue on the dishes. This suggestion is combined into a humorous and useful magnet that is kept on the front of the dishwasher. We flip it around to remember whether the dishwasher is dirty or clean.
We think guests respond better when things are expressed in a positive way. Happy guests means more repeat bookings.