It's a bit of a mix where I work TBH - I work in a university so there are lots of casually dressed academic members of staff with lots of support staff (of which I'm one), many of whom look much smarter! I tend to dress 'smart casual' most days i.e. trousers with tshirt or blouse plus a jacket but I do enjoy putting on my suit for any important meetings and always feel more confident the smarter I'm dressed.
We also have 'dress-down Friday' when most people wear jeans, but I'll only wear mine if I'm in the office all day with no meetings.
jan