I work for a super casual company now. I wear a t-shirt and jeans to work every day. They actually asked me on my interview why I was wearing a suit. As soon as I spoke, they could tell I wasnt a stuck up stiff "suit". I showed some personality, smiled and laughed a bit. On the other hand I have seen people come through here in hoodies who get the job. But I would personally never wear anything less than a suit to an interview.
That puts into words my vaguely-formed concept of why I defiantly wear dress pants and expensive shirts (+ suit and tie for interviews) even when working at a tech startup with 20-somethings in (carefully chosen) worn jeans and t-shirts.
If clothes don't matter, why am I being judged because I value aesthetics, not excluding the clothes I wear?
Because they do matter. The function of any level or style of dress at an interview is to mark you as part of the Right Group. This holds true even when the interviewers don't realize that they're unconsciously doing it.
Overdressing for an interview at some companies can put you in the Wrong Group just as surely as underdressing will at others.
You should always dress nicer for the interview than you expect to for the job. It has nothing to do with impressing the interviewer. I wore a tie to my interview because it made me feel important, which made me feel more confident, which made me come across as a more compelling candidate.
Use whatever tools you have to manipulate yourself into being the person (at least temporarily) who easily gets the job you want.
One company was 100% casual (don't wear a miniskirt and you are fine). The company was the biggest POS to work for.
Another company is business casual (occasionally they don't mind me wearing a t-shirt and jeans) and it is is just a pleasure to work at this one.
Edit: I actually like wearing business casual, very comfortable cloths.
I'm 26 and I find the trendy designer-esque throwback to the 80's an eye-sore that belongs in a circus, and a contradiction to the shouting cry for individuality when hipsters congregate.
Very nice. Put into words my vaguely-formed concept of why I won't be pulling out the suit for future interviews.
For interviews, the best advice I've heard is to remember that you're evaluating them as much as they are you. If they demand/care that you dress a certain way, perhaps it's a good sign you don't want to work there (unless you're into that kind of thing).
I have read posts that hint at a bit of hypocrisy in startups, though: "We wear t-shirts because clothes don't matter, but if you wear a suit you're unfit for startup hacker life." Bear that in mind if you really LOVE wearing suits. :P