Nowadays school uniform is not as formal as in past. To be honest I hate it. When I was a child our teacher used to say us that school uniform is needed. Once we asked why?
She politely explained us that if don't wear school uniform poor people will feel bad and jealous because they don't have such good clothes. I have uniform at my school. I don't mind wearing it because we are allowed to wear black slim jeans, coloured t-shits. I think this is fair to both types of students.