[SWTXBelle]

I taught at a private school where the kids had uniforms. I joked that teachers needed uniforms - we could have service bars, and medals for surviving difficult students (or parents!) To answer your question - I ended up wearing jumpers because any nice suits or dresses I wore would get ink on them, caught on a desk, torn, etc. Teachers don't have the salaries to wear designer clothes, or replace outfits all the time.
Jumpers are sturdy workhorses - especially if, like me, female teachers had to wear dresses (they still do - I quit only 7 years ago).