Why you might ask.  The answer is simple.  Your clothing influences how you feel about yourself and how others feel about you.  If you don’t look professional or appropriate, people my not want to work with you.  For example, I heard a story about a salesman going to sell to farmers in a suit and expensive clothes.  He was visiting the farmers in a field and stepped in all types of mud, etc with his expensive shoes.  All the farmers did was make fun of him for being foolish enough to dress that way when coming to see them.  He didn’t get the sale,

A better approach might have been to wear jeans or casual clothing in this situation.  If you are in a business, such as landscaping, suits are probably not the best approach when talking to potential clients.  They probably won’t expect them.  However, having a logo on your polo shirt or t-shirt goes a long way towards a more professional appearance.  Another way to make casual more professional is to have a dress code.  For example, your company logo on shirts with navy or khaki pants for all employees.  Everyone looks the part without being formal.

You do need to wear suits when it is appropriate for your business.  Occupations like banking, financial services, attorneys scream for a suit.  Not too many people want to take advice from an attorney in t-shirt and shorts.   Are you going to give your money to the person with a scruffy t-shirt and holes in their jeans – probably not.

The key is to analyze the customers you are trying to attract and dress in a way that makes them feel comfortable doing business with you.  Make sure you are not over or under dressing.  Remember that you are representing your business at all times and you never know who you may meet at the store.  Also, don’t forget referrals.  To get referrals you must be referable and when you are presentable people feel more comfortable referring you to their friends and colleagues.