In Australia. Thankful for uniform (my DD would have a hard time choosing 'an outfit' every day) but very thankful it's casual and cheap generic items are acceptable. No ties, button up shirts, blazers etc. Nothing that needs ironing!
I remember reading something where an American woman saw a load of British reception-age school kids and described the boys as looking like 'miniature estate agents'.
It seems so odd to expect kids to play in ties, shirts, etc. Not to mention girls 'having to' wear skirts etc.
My DC's uniform is dress (with bike shorts under), skort, shorts or pants (the pants can be tracksuit pants or 'jazz pants' - like slightly smarter leggings, not as tight) with a polo in short/long sleeves and either a cardi/sweatshirt/zip up fleece.
95% of kids wear sneakers, any colour or style is fine.
So much easier for kids to run around in and be comfortable, but still with options. Everything dries easily and no ironing. There's a real mix of 'uniform shop' items with logo and the super-cheap generic polo tops.
And no spending half of the PE lesson getting ready for PE! Kids just do PE in uniform, as it's all sportswear (except the dress I guess). I just make sure my DD wears sneakers, not sandals or boots, on PE day. Super easy.