If you have a very young puppy, not at all. until they are five weeks old. After that, it really depends on your dog’s lifestyle, skin and hair. A long or curly coat will obviously collect more nasties than a smooth, short one. But bathing too often can rob the skin and coat of its natural oils, causing it to lose its sheen, or even making it harsh and dry. To keep your dog looking and smelling clean between baths, give them a regular brush and trim.