Five bottles of flea and tick shampoo (at $4.23 a bottle) just arrived from Amazon. This is old school pyrethrin shampoo made from Chrysanthemums. So safe, it’s licensed for food production factories.
I wash my dogs nearly every week after hunting in spring, summer, and fall. I've had no skin problems with any dogs in 50 years, and no fleas or ticks either. As always, use what you want. My own thoughts and reasons for what I do are at the links below.