Most people would agree that parents should be financially responsible for their children at least to the best of their abilities. Child support amounts can be modified if situations warrant. In most jurisdictions and New Mexico is no exception, child support can be modified whenever there is a change in circumstances. The parent alleging the change in circumstances has the burden of proving that there has been a "significant change in circumstances."
In New Mexico, anytime there is a significant change in custody, you should have an attached child support worksheet. § 40-4-11.4(A) NMSA 1978 provides: "A court may modify a child support obligation upon a showing of material and substantial changes in circumstances subsequent to the adjudication of the pre-existing order. There shall be a presumption of material and substantial changes in circumstances if application of the child support guidelines in §40-4-11.1 NMSA 1978 would result in a deviation upward or downward of more than twenty percent of the existing child support obligation and the petition for modification is filed more than one year after the filing of the pre-existing order."
A 20% change in support and a year wait are fairly significant changes for a Court to entertain a child support modification. Generally, if any moderately significant provision of child custody changes, then the court will also draft a new child support worksheet. Many courts will also review child support simply if it has been a significant period of time since the child support obligation was put in place.
In order to get the Court to reconsider and possibly modify child support, you have to first file a motion with the Court outlining the grounds for granting a modification to the current child support. Grounds must be within the criteria outlined in the statute cited above. This is generally the rule in whatever jurisdiction your case is in.
By the way, the statute also provides in § 40-4-11.4(B) that parents are obligated to exchange financial information each year if one of them requests it. The information includes Federal and State Tax Returns, 1099s, W-2s, information about daycare, and medical expenses. You can also ask the other parent to provide more information. This is done by means of sending the other parent interrogatories and requests for production.
The information you request must be rationally related to the questions of child support, income, and budget unless the scope of your evidentiary hearing is beyond the issue(s) of child support. This gathering of information is called the “Discovery Process” and it is provided for in the Rules of Civil Procedure and elsewhere.
One caveat, if you are trying to keep the costs of litigation and attorney fees in check, you may wish to consider limiting discovery to only those items, questions, and pieces of information and other evidence which are essential to the upcoming hearing. Fishing expeditions, attempts to bog the other parent down in paperwork, and being overly a pain in the neck will be costly to you in the end.