Costumers: Look the Part?

I once overheard a statement that confused me. "Costumers have to always look good/fashionable. I mean it's there thing." The speaker was implying that other technicians can look grungy or not quite put together since their area is not dealing with clothing, makeup, or hair. 

Six years ago wearing an 80's prom dress.

I disagree with this statement. It is reminiscent of a brain teaser my father once told me:

"A town has two hairdressers. The first has a lovely haircut and pristine shop. The second has a patchy haircut and there is hair all over his shop. Which do you go to? The second of course. He cut the first's hair and the hair on the ground shows he has many customers."
I think each costume technician should dress how he or she wants; except distressing. When distressing do NOT wear your favorite outfit. You WILL ruin it! Everyone uses clothing to express themselves. This is why the clothing industry is so big. 

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I know you should dress for success, but does dressing with today's fashion equal success for costumers? I do not think this is the case. I prefer to be my own person, and if that means not being dressed to the nines one day, so be it. Although, let's be realistic, I'm ALWAYS dressed to the nines (she says with a laugh).

Question of the Post

Do you think costumers should hold themselves to a high standard of fashion because of their position?

Why?