I got my puppy at 12 weeks of age, so 3 months roughly, and she stunk to high heaven so I gave her a bath. I gave her another, with a flea and tick shampoo, at about 5 or 6 months and it actually seemed to make her itch a lot more! She's 2 1/2 yrs old now, and outside of swimming, she's only had 2 baths since. I think bathing a puppy every month or two is okay, if need be, but more than that isn't good as it removes their natural oils and "can" cause itching or other skin issues.
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain