Your Yorkshire will be a lot more pleasant to hold and pet if he’s clean and fresh-smelling, and that means he needs regular baths, just as you do. For some reason, the myth got started years ago that bathing a Yorkshire (in general all dogs) too often is bad for their coats. Perhaps that’s true if you use harsh shampoos, but keep in mind that show dogs are often bathed several times a week, and have gorgeous coats.