By statute, Texas law presumes that a parent who does not have a child’s primary physical residence will pay child support to the parent or conservator providing the child’s primary physical residence. This presumption results from the application of child support guidelines to the paying party’s income or resources. These guidelines consider, among other factors, the age of the child, the paying parent’s income and ability to contribute to the child’s support, any alimony or spousal maintenance being paid, the amount of time the paying parent has possession of or access to the child, as well as any special needs or requirements of the child. The strict application of the guidelines is not absolutely required in every case. The court may vary the application of the child support guidelines based upon its determination of the best interest of the child, even if the parties reach agreement concerning support.