As stated previously most work placements have a uniform...
School Uniforms
As stated previously most work placements have a uniform or workplace attire policy, so unless the majority of students intend on either being self-employed and working from home or being unemployed, which I doubt, then not wearing a uniform at school hardly seems a relevant issue especially if it improves the educational environment. Most adults who wear a uniform or formal work attire seem to cope with wearing it for 8 hours per day 5 days a week without it seriously impairing their personality or self expression, so I'm sure a student can do likewise for the short period of their life while they attend school. As for cost, it is cheaper to have a uniform with the associated positive benefits than it would be to have 5 separate casual outfits with footwear, etc, assuming that the student is going to wear the same 5 outfits for the whole year and in all weather conditions. Wearing casual clothing would bring into play the "haves and have nots" issue where peers look down upon those who either don't have or can't afford the latest fashion items. Peer pressure can lead to bullying, low self esteem, depression with associated problems such as self-harming, drugs, alcohol abuse, theft and possibly suicide. Peer pressure can also find itself transferred onto parents of students, forcing them to take on debts for clothing they can't afford leading them into financial difficulties.