How often should I wash my dog?

Dogs are not like human beings. That being said, they shouldn't be washed as regularly as us.

People who own small dogs with long hair, usually wash their dogs in a weekly basis. That is because of the smell that can accumulate in their coat. But that is far from being a rule. If your dog doesn't need baths this often, you can surely wait a few weeks (or even months) to bathe him.

Of course, the owner should brush and inspect the dog in a regular basis - and the bathe time can be used for this, too.

As needed. By this, I mean there isn't a set schedule, like once a week or once a month, etc. if you think your dog smells, looks, or feels dirty, then a bath is a good idea. Otherwise, no need to worry. Just make sure to use a mild dog shampoo, and follow up with a soothing/moisturizing conditioner to prevent skin from drying, and to keep the coat soft and prevent mats. The most important things to remember are don't overbathe, completely rinse all shampoo, and only used shampoo for dogs, as the ph levels can differ amoung different species. Human shampoo will be more harsh on a dog's skin. Only use a dryer, if preferred. I usually just towel dry. Again, because it's easier on the skin and coat.

Not too often! In doing so you may strip their coat of its natural protective oils, thus causing skin problems. If your dog's coat is overly greasy, scratchy, or has a strange smell, visit your veterinarian for further testing.

Definitely bathe a dog as needed (like if they're muddy or otherwise dirty) but you don't need to bathe them often. You will want to buy specific shampoo for dogs for the previously mentioned ph level issue. If the dog has a long coat I would recommend a dryer just so you don't run into any fungus issues. If the dog has a short coat, towel or air drying should be fine.

Dogs really don't or shouldn't need baths all that often. Most dogs do best if left to let their natural oils and fur be at its best. Some dogs need the occasional bath because they got super dirty or by a vet's direction, however most dogs should be fine with only a few baths a year.

As others have said, it's best to bathe as needed but not frequently. Soap can strip the dogs fur of their natural oils, and if not rinsed properly can leave harmful residue on the dog, irritating the skin. Some dogs are fine to bathe every four or five months. Others get stinky sooner than that, others later.