If you are each making the same amount of money and each had the children half of the time, then neither of you would have to pay child support to the other. Of course, under those circumstances, if the children were in private school or went to summer camp, you would probably each have to contribute 50% to that expense.
Then, there are questions of health insurance coverage for the children and the cost of same, along with contributions for unreimbursed medical, dental and other health care expenses.
If, however, the two of you do not earn the same amount of money, then there are calculations to be done to determine how much one of you would pay to the other. Under this scenario, the person earning more would have to pay a specific amount of money to the person who makes less.
It is important to realize that Federal mandates have existed requiring each state to enact a child support formula for the calculation of child support
(lest the state run the risk of losing Federal funding). Each of the fifty states has such a formula, though the contents of each State’s formula varies. Length of time with the children is but a single factor to be considered along with income of the respective parties, income (if any) of the child or children), and special needs of the children.
Under these circumstances, there would also have to be a factoring in to the child support equation issues of alimony (or spousal maintenance).
In addition to insurance and unreimbursed expenses, there will be issues of child care, private school (if appropriate), summer camp, and related expenses.
There is of course an added issue of who will pay for the clothing.
Consequently, this relatively simple question has a complicated response.