One of my favorite stories centers on a dress code change that occured when I worked for a Fortune 500 retailer in its national headquarters.  The company chose to go from formal business attire to business casual.  Shortly after that dress code change, the company entered into a multi-year sales decline.  To the irritation of my supervisor, I would regularly point out that the company's sales woes began when employees got to dress more comfortably.

With the lax dress code came a less intense focus on business, I would joke.

While there is no cause and effect relationship here, and the words more intended as a joke, the issue of your organization having a formal and published dress code is an important one because  the appearance of your employees is a direct link to your company's image and branding.  How your team dresses is in fact itself a message being delivered to your customers and vendors.

Many young workers who are new to the professional working environment may not even know what is appropriate attire.  Your dress code should specifically spell out your organization's expectations.  Once the formal dress code is developed, all employees should receive a printed copy.  Annually all employees should be given a refresher reminder on your dress code.

Nothing can drive internal resentment faster than employees who do not dress professionally or appropriately.