Smartness of appearance - how important?

How important is it to have smart looking employees when visiting customers in their businesses or homes?
Surely in today's relaxed and informal world this is no longer as important as it might have been 10 or 15 years ago?
Well, we think it is vital to have very smart and clean looking handymen calling on customers. People may be dressing more casually in their private lives but they still want, and expect, that when they call someone to their home or place of work that they look professional. The other point here is that a uniform does also allow the customer to immediately identify who has arrived at their door, and to feel comfortable letting them into their home. This especially applies to the elderly and women on their own.
We spend a huge amount of time (and money) on keeping our guys looking the part, and it's definitely worth it from the feedback we receive from happy customers.