Child support is a way for a noncustodial parent to help pay for the expenses of the children because it isn't right for one parent to shoulder the entire financial burden of the kids. For the most part, the child support is ordered by the court, which means that the paying parent must cover at least that amount. It doesn't mean that it is the maximum that the parent can spend on their children.
While many people think about the regularly recurring payments from one parent to the other when they think about child support, this isn't the only thing that these orders cover. The court will usually set the standard for which parent needs to include the child on their health insurance coverage. Another consideration is who will pay the extraordinary medical expenses for the child.
Parents who are divorced need to budget for those payments. It doesn't matter which side of the matter you are on. If you are making those payments, you must ensure that the money is available. If you are the recipient, you should set your budget to use them as a windfall just in case they are late.
Some parents balk at the idea of having to pay child support, but this isn't something that should be seen as a negative action. Children are expensive. There isn't any reason why one parent should be left having to cover all of the costs of raising a child that it took two parents to make. We know that child support is sometimes a touchy subject, but it is one that must be addressed.