If the written agreement is written up in a clear and concise way setting forth the terms of the child support and visitation agreement it should be legally binding in the vent of a dispute even if it is written up by the agreeing parties without a lawyer's involvement in it.To be on the safe side, the agreement should be initialed on every page by the parties who sign and date it. Their signatures should be notarized to prevent any future issues that one did not sign or initial the documents.Additionally, if there is already a court filing as to the dispute, the agreement should be filed with the court and an order from the judge declaring the written agreement as the standing agreement between the parties should be issued and filed in the case.Good question.