We all know how important word of mouth recommendations are. The most credible recommendation you can have are that of a Veterinarian. I have been told by 2 Veterinarians that they recommend me not only because of the nice haircuts they see but because of how thorough I am about ear plucking and cleaning. Think about how many exams a day a Vet performs and how many ears they look into.
People in all walks of life, when asked for a referral, will refer to the people they know do a good job. I have found that you can groom a dog to such perfection that it could walk into Westminster, but if you are not consistent with the basics a Veterinarian will be the first one to have a less than satisfactory opinion of your work.
Just another way to increase your profitability.