The first measuring stick for business attire should be cleanliness. Clients prefer their professionals looking well groomed. Casual dressing is no excuse for looking sloppy, rumpled, or unwashed.
When in doubt as to the correct attire for a specific business meeting, opt for a suit. Dress-down wear is still relatively new to the corporate arena and still not perceived as professional and powerful as the classic business ensemble.
If unsure about an occasion’s level of formality, overdressing is the safer bet. By dressing up, not only do you pay a compliment to your client, cohort, or company, but you always have the option of removing one or more articles of clothing.
Dress in line with your superiors and never more casually than your subordinates. Be careful not to dress in such a relaxed manner that you no longer look like someone who can become an authority figure.
Whatever clothes you choose to wear to work, make sure they have the same characteristics that you look for in a fine suit: good material, fine workmanship, and excellent fit. Buy the best quality you can afford. Like one’s education, clothing is an investment in your future.