Those are considered extras...ask for specific amounts to cover these. I see many orders here that are vague in regards to stating "extras that both parties agree with will be split 50/50". Then one parent disagrees on something that used to be the norm and the other parent gets stuck with paying for it.
If child requires school uniforms then try to agree on an average amount and ask that it be split...if the child does dance every year then average that as well. Don't overdo it but do have correct expectations.
My 2nd ex does not pay ANY extras, school tuition or school uniforms nor any extracurriculars as I did not think to add that in and he sure isn't offering. My first ex pays $50 once per year toward a sport, not much but it helps. However it is something not court ordered but agreed upon seperately.