Des - Our dogs have thier coats for a important reason. Thier metabolism work with thier coats to protect the dog. The only reason for trimming a coat is for health concens, If a dog is matted badly, or maybe tick infected are possible reasons, another is sanitation especially in older dogs with renal failure. I saved my Irish wouldhound one summer after a romp in the marsh and getting skunked all in one glorious dog adventure night. He was about 5 y.o. and his fur came back fine. I also shaved just the belly of my Malamute for sanatation(renal failure).