The way you dress affects your performance. Or does it? This week’s poll was a close one with 54% stating that dress code is a factor in the way you behave and are perceived, and 46% saying that they’re just clothes and don’t really matter.

My view is that dress code matters. It matters a lot. Clients, partners and co-workers will make assumptions based on your appearance. Of course, first impressions in say a new business pitch are vital. If you want your ideas to be taken seriously, then you have to look credible. That might mean wearing a suit or business casual depending on the norms of your location, but you want your prospective client to see you, not your clothes.

Here’s a little guideline which I often share for those in doubt: Always dress more smartly than your client. This shows respect. You can always remove your jacket, loosen your tie or roll up your sleeves if you want be be more casual during the meeting. For in-house teams, the same is true, if you want your agency to take you seriously and you value the relationship, those Birkenstocks, sandals and jeans have gotta stay in the wardrobe. Perhaps I’m old-fashioned but I think this stuff is important.

Within the agency, I’ve also noticed that dress code changes the way people behave and interact. On Fridays, like many firms, we have a dress down policy so jeans and sneakers are good. I’ve noticed on these days that people inter-relate differently. They’re more personal, they spend more time talking by each other’s desk, the atmosphere is more relaxed. Now that might be the impending weekend, but I think there is a benefit here in building culture where people get to know each other better. Perhaps it’s slightly more creative since people are more confident to voice their ideas. At the same time though, there’s sometimes less zip, things take longer to complete, errors can creep in as people take their eye off the ball. Ever tried conducting a formal appraisal where you’re both casually dressed? Just lacks the required gravitas.

Adhering to a more formal dress code, whether that be business casual or suits, does take discipline. There’s always a gravitational pull toward the casual. I think those who make the effort will reap rewards in terms of credibility by showing their clients and colleagues respect. So dress code not only affects performance, it also reflects it.