I'm a young engineer (in the oil and gas industry) and thus like other engineers usually dress in an ironed shirt and pants. I have however seen that people in other departments (and especially the managers) wear a suit to work. Assuming that at some point of time I would work my way up to that position, when would I start needing to dress differently?
Also, on the same note, does the attire affect things like promotion and roles?
Yes attire can have an influence on promotion. As you move up the ladder, you often have more client-facing tasks and no one is going to promote someone they think might be an embarrassment. Further, how you dress influences what people think of you and how seriously they take you. So no grungy clothes, t-shirts, sandals, too sexy or too tight clothes if you want to make the move into senior managment someday.
In some professions people think they can dress how they want and that is one of the perks. But I have noticed that the grungier or lessformally dressed the person, the less likely they are to be selected for management responsibilities. Now that suits many people just fine (especially in the software world where I work), they don't want to be managers. But if you aspire to be a manager, then you need to dress like the managers not non-managers.
Smart money has always been on dressing for the position you want to have not the one you do have.
I agree with HLGEM above. Just adding a facet about "when to start" and building a wardrobe.
If you're going to do this, you'll have to accept that will take a long time and a considerable investment to put together a good wardrobe of suits, jackets, shirts, sweaters, trousers, and shoes. So, yes, start now and build it up gradually piece by piece.
It is best to invest in very high quality stuff with tailored alterations. Start with wool slacks and fitted shirts. If you get the good stuff it will be even more comfortable and look better than your typical department store business-casual. There is a little variability with wearing a suit, you might get away with a jacket and appropriate slacks or even a nice sweater. Younger folks can get away with less conservative but still elegant and fashionable choices (ymmv depending on culture).
Over time it will become integrated into your appearance and the expectations people have about how you look.
