In the roughly 10 times I've stayed in an Airbnb I've never had an issue with the condition I've left the place. Often times my family (and dog) have made a mess, but always do some clean-up before leaving. Cleaning fees are typically $20-60 for the stay which seems reasonable for cleaning an entire home. Normally the airbnb service fees are larger than the cleaning fee. There are certainly some hosts who are charging high cleaning fees to lower their nightly amount, however.