I have a 2-year-old GSD who probably gets washed once every two weeks. I just had a friend lecture me that this is way too much as it strips is natural oils etc (which I am aware of). However, he gets EXTREMELY muddy on his walks and will take a dip in a muddy puddle any chance he gets. His coat is lovely and he often gets complimented on it. Should I cut back? We've tried just using a washcloth/brushing but that doesn't help with his coat clumping up with mud which he then chews at. Any suggestions would be greatly appreciated!