"Waffle trousers"?
Is it a bad idea to discourage that brand of individuality at such a young age, or is it wise to show children that they are all equal in the school system, with no one pupil beating the other in terms of dress (I know that isn't the only reason they exist, but I like that idea nonetheless)?
And they buy the designer clothes anyway for after school and weekends. So its uniforms and designer clothes not uniforms or designers clothes.
The thought of kitting out a 13 year old girl in designer clothes each day is terrifying.
Here's some of the list from the local girls' high....
Junior Skirt 56cm – 107cm $85.00
Senior Skirt 56cm – 107cm $90.00
Short/Long Sleeve Blouse 8 – 24 $60.00
Navy Jersey 82cm – 122cm $80.00
Red Jersey 82cm – 122cm $65.00
So based on 5 Blouses, a jersey of each colour, and 2 skirts, that's $590, not including stockings and shoes, which could be another $90-$150, or the uniform for Phys Ed which is another $200+ for 2 polos, trackpants and shorts.
With kids growing out of their uniforms very quickly, many prep schools here in the UK sell second-hand clothing in the school shop. I don't know how popular it is, though.
While everyone agreed it was a good thing to get more use out of clothes that kids quickly grow out of, when it came down to dressing their own precious offspring in someone else's castoffs, they couldn't quite bring themselves to do it.
I don't know, have you seen the prices of uniforms? Designer clothes are likely cheaper.
Why would you buy a 13-year-old girl clothes from Coco Chanel or Jean-Paul Gaultier? What boys wear Armani suits to junior high? Maybe I'm misunderstanding what is meant by "designer clothes".
If kids really want status-competition clothes, they can wait until they can legally get a job and pay for it themselves.

I've always hated the very idea of uniforms. I can only understand their use when there is a practical need for them (such as in the military or with law enforcement) otherwise I oppose them as a dehumanizing violation of personal liberty and expression.
But you can see how they can promote an egalitarian effect surely? In such a setting, children can experience freedom from prejudice.
Kids DO judge other kids on their clothes. More expensive, or trendy designer clothes (I'm not talking Burberry, but the stuff is still expensive) means a higher social standing. Wearing Wal-Mart clothes in a middle school or high school full of Tommy, Vena Cava, and Juicy Couture is akin to cruel and unusual punishment, because the Wal-Mart kids WILL get picked on and singled out for abuse.
But you can see how they can promote an egalitarian effect surely? In such a setting, children can experience freedom from prejudice.
Even if every child wore exactly the same quality uniforms supplied by exactly the same manufacturer and all of the clothes were provided free of cost to the students so that none of them were over-worn or hand-me-downs I am confident they would have no problem finding ways to discriminate against each other. That's just the way kids are.