All through primary school then I moved to Europe so no uniforms for a while and then I moved back to Australia and every high school has them so I found a place that doesn't. I don't know about other countries but here uniform in high schools is insane it's like you have to wear a tie and a blazer and the right color and length socks and there is only one type of shoes the girls can wear, only one color hair tie you can use etc.. and if you don't have everything right you get detention a told off. I think uniform in high school is a waste of time and it messes but the priories of the teaching staff.
I've always had to and I still have to. :/ Not always the best looking, but at least we don't have to spend half an hour picking a 'nice' outfit to wear to impress. You can't really tell if a person is disadvantaged either, which is a good thing.
I went to 3 different elementary schools, and I had to wear a uniform in one of them (3rd grade). It was in Greek-American Institute in Bronx, NY. It was no big deal. It was a basic suit that most men wear to a job at the office.
LOL I was the first graduating class in my school who had to wear the uniforms, thank god we only had to wear them for one year because we graduated that year. I hated the uniforms and often got in trouble for refusing to wear it.