Okay, now that I hooked you with a bad movie reference, lets talk about laches. Laches has been defined in New Jersey family law as "… an equitable doctrine which penalizes knowing inaction by a party with a legal right from enforcing that right after passage of such a period of time that prejudice has resulted to the other parent, so that it would be inequitable to enforce the right." Put simply, it is sitting on your rights and doing nothing about it for many years and when you do try to enforce your rights, the other party would be unduly prejudiced by the delay.
The issue recently came up in the case of Mayer v. Mayer, an unreported (non-precedential) decision released on January 25. 2013 involving a situation where the support payor overpaid child support for 7 years. Though the overpayment was indisputable, the beneficiary of this overpayment fought repayment of it claiming laches and other equitable remedies as a defense. The trial court did not address these defenses and simply ordered that the child support be reduced by $42 week to pay back this more than $35,000 overpayment and also entered judgment against the recipient.