Child support orders cannot be changed on a whim or because a court thinks that “it is time.” It must be based on evidence proving that there is good reason to make the change. This usually requires that a person who wants to make the change show a changed circumstance. You must show that the facts that existed when the last order was entered have changed. (In the many years a child support order is in place, the parent’s circumstances may change many times.) For example, in Maryland, if one parent’s income has changed (either gone up or down) by at least 25%, this is considered a big enough change to require a change in the support order. You can request a modification for a lesser change in income, but will not necessarily be guaranteed a change in the support order.

Many different scenarios can create changed circumstances. For example, if the paying parent has had a large increase in income, the court can order the child support increased. Or, if the child's needs grow, such as if the child becomes ill or disabled, the amount of support can be ordered raised. Sometimes the mere passage of time creates the changed circumstances. For example, as a child grows older, it becomes more expensive to buy clothes, food and other necessities. These increased expenses can be enough to justify a raise in the support order.

Support can also be reduced if you can show why this would be fair. For example, support payments may be reduced if the custodial parent inherits money, gets a large raise or otherwise has an increased ability to support the children. Or, if the paying parent loses his or her job, the court can be asked to reduce support during the period of unemployment.

A mistake many parents make is to reach informal oral agreements modifying child support. This can lead to future problems. For example, the following scenario is very common:

Peter paid his former wife Alice $400 a month to support their son. When Peter was laid off, he called Alice and said, “I just got laid off. I can’t afford to pay $400 right now.” Alice responded, “Okay. Pay $100 for now.”

Ten months later, Peter was rehired and raised his support payments back to $400. During his layoff, Peter had made 10 payments of $100. Alice called and told Peter she expected him to pay the $3000 he had not paid during the layoff. Peter replied that he did not owe the money because they had agreed to the child support reduction during his layoff. Alice disagreed. She claimed that she had not given up the right to $400 a month but had merely permitted Peter to defer full payment until he was rehired.

When Peter refused to pay, Alice took him to court. The judge ruled that the evidence did not support Peter’s claim that he was excused from $300 per month of his support during his layoff. He was ordered to pay the $3000 to Alice at the rate of $100 a month, in addition to the usual payments of monthly support.

The problem with oral agreements is that they are often vaguely worded and the memories or understanding of the parties may often differ. Any agreement you make to modify child support should be put in writing so that there are no misunderstandings later on. It is also a good idea to have a judge sign a court order based on the agreement.