Not to argue, but there are generalizations and assumptions that are sometimes made that may not hold true all the time. My babies both have always been bathed once a week in Aussie MOIST shampoo and conditioner. NO issues yet.
Preston is two years old, we got him when he was 5 months. I have tried numerous dog shampoos in the year and a half that we have had him. I always come back to AUSSIE MOIST shampoo and conditioner (the human kind). All of the dog shampoos tend to break him out and cause skin issues ( he is also allergic to frontline and advantage to the extent that my vet made me report it to the EPA) Anyway, every time we go in, the vet and staff comment on how nice his hair is, how good he smells, and how good his skin looks, anytime there is someone new in the office, they ask what I use. They are always surprised when I tell them.
I think the key as someone else said is to make sure you don't use too much. Humans have a tendency to do that with their own hair also, It doesn't take near as much shampoo as you think to really get your hair (or your dogs coat) clean.