I agree with Rachlou that “How crumpled your shirts are is nothing compared to whether your bridge will stand“ and with Bj1111 that clothing can be a false signifier, just like that stack of papers on your desk can make it look like you’re working. That’s why I think some fields that are focused on knowledge, like tech and academia, give people a hard time for overdressing—spend your time on your work, not your appearance!
I had a colleague in grad school who did the whole 9 yards—perfectly curled and coiffed hair every day, manicures (no one else I knew got them), full face of makeup, dressed to a T. She told me the reason she did it was that her writing was very feminist (still is, and she has become a leader in women’s studies) and she had seen women get written off as “women’s studies dykes” or similar, so her appearance was a way of disabling that critique. I don’t know what happened when she first arrived and was the only woman—for all I know there may have been concerns she was going to spend more time on make-up than on work— but by the time I got there and we were 5 out of about 30, absolutely no one criticized her appearance—because she did the work, had a list of conference presentations and publications as long as your arm, and was a good teacher. A few years and 6 more women in the dept later, I was told that I was the power dresser, because I wore old cut-offs to class, showing confidence in my skills in the classroom.
Of course, when I go somewhere where the work itself is about appearance, then it doesn’t bother me to see people who spend time on theirs. But their work on others is still more important to me—that, not dressing themselves, is their job. After a single mom drssses her kid(s) and her clients, she should expend energy on her own appearance? Eyeroll. It isn’t just foolish to judge by that standard, it’s also terribly unfair. Why do some women judge other women’s appearances so damn harshly and ignore the structures in society that leave people, often women, in overwhelming situations?
You can dress up if you like. You can dress down if you like. Dressing according to what’s expected can make things a little easier for you in the beginning, but eventually it should come down to whether you are doing the work or not. I don’t think age gives you license to do anything differently (and you can be judged for being too old in some fields) but like the grad school colleague above, once you’ve proved your mettle, you have much more leeway to dress how you wish, whether that’s fancy or not.