@Mallory65 I don't accept guest pets, but I've had dogs all my life. I disagree that a pet fee should be returned if the dog doesn't "destroy" anything. The pet fee is meant to cover the extra cleaning involved in dealing with pet hair, smells, land mines in the yard if the guests don't clean up. If a dog destroys something, that's damage and the guests should be charged for it additionally, although Airbnb for some clueless reason, doesn't let hosts claim for pet damage, so you have to simply refer to it as damage.
I feel the same about big versus small dogs, because small dogs are more likely to be used to sleeping on the bed and furniture, small dog owners tend to treat them like babies and don't necessarily think they need training or discipline, thinking everything they do is cute, and in my experience, are more likely to relieve themselves indoors, maybe because the owners, thinking of them as their babies, don't consider it any big deal. They also tend to be yappers.
But a host on another forum who also runs a small dog boarding business pointed out that small dogs' nails don't scratch as deep, there's less hair to clean up, and a few other things I can't remember.