The answer depends on several factors such as the amount of client interaction, the type of clients, the type of work, the office culture/environment, and social norms. So, the answer is "yes", "no", and "sometimes".
How Do You Create a Dress Code?
WHY. Clearly state the "Why?". What is the business purpose of a dress code? Remember, times have and are changing . Is what someone wears important to the job they do? Is it a safety issue?
YES. Establish what to wear. Provide guidelines and examples of what clothing is appropriate for you business.
NO. Establish what not to wear. Be specific about what you won't allow.
THEN WHAT. Determine the consequences and train your managers how to administer them. Article: How to Address a Work Dress Code Problem
EXCEPT. Decide on exceptions such as Jeans Friday, casual holiday, or dress up Halloween.
LET'S TALK. Revisit your dress code each year to make adjustments. If a rule no longer has impact, remove it. If a need has come up, establish a policy to fill the need.
You have help!
Your Advisor HR Field Consultant Can ...
Help you decide if and why you need a dress code
Help you determine how to write, roll out and enforce the policy
Coach you in talking to employees who are not adhering to the code.