If you do have a joint custody arrangement, maintain detailed and organized financial records of your expenses. Keep receipts for groceries, school and after-school activities, clothing, and medical care. At some point your ex may claim she or he has spent more money on the kids than you have, and a judge will appreciate your detailed records.

For more information on child custody arrangements, see Building a Parenting Agreement That Works: How to Put Your Kids First When Your Marriage Doesn't Last, by Mimi E. Lyster.