With Child Support, the law is clear; generally one parent must provide child support to the other. A formula is used to calculate a worksheet, whereby the parents enter their gross monthly incomes, each parents' number of overnights per year, health insurance premiums for the children and any day care costs. The worksheet then calculates a child support amount. When circumstances shift this amount between parties by 10% or more, the parties may move the Court to modify the child support amount.

One thing to keep in mind is that the child support amount MUST be modified by the Court to become legally valid and enforceable. Often the parties will agree informally that as circumstances have changed, they stipulate to modify child support verbally. For instance, a woman may tell her ex–spouse that he can pay $100 less per month. This works fine for a while, but if the relationship becomes strained over a future issue, sometimes the father is surprised to find that his former wife believes he owes $100 per month for the past few years plus interest. The court must approve all modifications if they are to become valid.

Maintenance can be modified if it doesn't state otherwise in the parties' Agreement or Court Order. Unlike Child Support, Maintenance or modern alimony is not based upon a concise formula other than temporary maintenance. Rather, myriad factors are considered, including the parties' income, the lifestyle enjoyed during their marriage, the parties' education, ability to support themselves, property awarded to or held by them and the length of the marriage, among other things. Maintenance is subjective as Courts vary on the duration and amount; therefore it is an important issue to mediate.