Every time its eyes are dirty! This is often the case when you come back from a walk, especially if you went to the beach or on a dusty road, but also in the morning when it wakes up.
There is no real rule concerning the frequency of washes. This depends on several factors: environment, your dog’s lifestyle, the length and type of hair around the eyes, etc. On average, you can wash your dog’s eyes once to three times a week. If you think you need to do it more frequently, ask your veterinarian to check that everything is alright!