Here are the policy considerations behind the state's guideline formula: http://www.kscourts.org/rules-procedures-forms/child-support-guidelines/faq.asp
The custodial parent is not expected to provide for the child's needs during periods of visitation - that is the obligation of the parent with visitation.
While some parents will send clothes back in forth (since the children grow so fast, it saves both parents money) they rarely send daily hygiene items unless a child chooses to pack something. However, the courts presume that each parent will have all of the child's basic necessities available during the time that the respective parent has with the child.
Of course, the court order can specify otherwise, and state that the custodial parent is to pack for the child prior to visitation, but that is atypical.
Also, it won't look bad to stop doing something that is not court ordered; one can provide notice so that the other parent can go out and get the items they began relying on the other parent to provide for them.
The child support obligation is so that the custodial parent has adequate means to support the child. The custodial parent need not reimburse the other parent for clothing purchases. The obligor parent also cannot determine how child support is to be paid, that is at the discretion of the parent. And there is no requirement that a child's hair cut must be in a salon; many families use clippers at home, especially for boys.
The child support payment does not take care of all of the child's needs- just those that the custodial parent is responsible for.