“Dress for the job you want, not the job you have.”

That is a nice maxim that I got by today and it got me wondering. Being on a technical role myself I do not dress very well at office. I'm not wearing rugs but I'm not even close to the business-casual realm let alone the costume one. Do you think that the way a technical employee dresses is important? Do you dress up at the office? Do you think the way you dress played a role in a promotion you got or lost?