You can't judge a book by the cover, but you can always look at the cover to decide whether or not to read the book. Your appearance may not be an indicator or your work capabilities, but you probably won't get the chance to prove your value if your appearance doesn't meet the employer's expectations.

Don't rely on a company's dress code as a guide for what to wear during an interview. The interview and the job are entirely different and require different appearances and different behaviors.

By dressing appropriately for an interview, you're showing the employer that you have respect for them and the company. This level of respect is rare in today's labor market.

People who look good usually feel good about themselves. This translates into confidence during interviews.

Even if you're applying for a job that doesn't require you to wear nice clothes or a suit, it's still a good idea to spiff up the interview. Think of the interview as a first date. Your chances of getting a second date (second interview) are always better if you make a solid first impression.

Employers are afraid of incongruous appearance. They want someone who talks like a good employee, looks like a good employee and behaves like a good employee. If there's any inconsistency, you may not get the chance to prove you're a good employee.