The frequency of bathing a pet dog depends on several factors such as the dog's breed, activity level, and coat type. In general, most dogs do not need to be bathed more than once a month. Over-bathing can strip their skin of natural oils and lead to skin issues. However, dogs that spend a lot of time outdoors or have skin conditions may need more frequent baths as advised by a veterinarian. It's best to consult with your vet to determine the appropriate bathing schedule for your specific dog.