Some wear suits, some wear shorts and golf shirts, and there are all manners in between. Part depends on whether you're working in Manhattan or in a beach resort community. Part depends on your knowledge of and relationship with your clients.
What you wear is part of your first impression. It's one of the aspects of nonverbal communication, along with posture, gestures, facial expressions, and eye contact. When you meet someone, all of these nonverbals can be ten times more effective than words, according to Bill Acheson.
He also quotes research stating that people get a first impression in 1/24 of a second and that slightly after one second the impression is so strong that it's very difficult to change.
Do you wear a name tag to the grocery store? Is your image consistent? Do you wear a logo shirt to the Little League game? Is your image consistent? Do you have a personalized license plate, a web logo or a sign on your car? Is your driving consistent?
We're constantly making first impressions, to those we know and those we don't know. Give some thought to what that first impression is.