We charge a one-time non-refundable $500 pet fee and $20/month pet rent per pet! So if someone has 2 dogs, thats $1K off the bat. We have more pets than people in my building and they are pampered! The costs go toward additional common area and elevator cleanup for frequent accidents, a pet concierge service that provides treats, pet of the month awards, new move in pet gifts, and pet events for the building. We do not have any pet amenities such as a dog run or pet spa. From a marketing perspective it makes sense to cater to pet owners and they will pay these fees without blinking an eye- that's just the cost of pet ownership.
As far as ESAs go, we started using PetScreening, a 3rd party company that ALL residents must register with, even if they are not a pet owner. Pet owners pay $20/year and submit all of their documents, including ESA docs. PetScreening analyzes their information and presents it to us to make a final determination on pet/ESA. If the resident can't/won't submit the correct documents, then we charge them pet rent.