The number of pets, to be proper and convenient depends on several factors in the home. First is the space. If you are living in a small apartment then 1 pet is enough otherwise it will pose a problem. We live in a 3-bedroom house with a backyard and front yard totaling 100 square meters. Our 2 dogs are very comfortable and they are convenient with their toilet habits outside the house. I'd say that the optimum number of pets for us is maybe 4.