Does appearance matter in most engineering jobs?

I just started college to pursue an electrical engineering major. I was just wondering if most engineering jobs, in general, require a lot of personal interaction, in which case I would have to wear a suit and stay clean cut. Or could I show up to work dressed casually with a beard and hair below my shoulders. I know that I would have to look my best for any interview in order to get a job, but once I get hired, will people care how I look.

Any advice from personal experience is much appreciated.

Thanks