Yes. It is very important to keep a notebook with the following columns: Date Due, Amount, Date Paid, Arrearages, Check Number. No payment should either be made or taken in cash, since there will always be a disagreement later or about whether a payment was made. Such disagreements create unnecessary court hearings. Judges generally will give no credit for payments claimed to have been made in cash. It is usually cheaper to be accurate about all payments made or received, than to attempt to gain an advantage. That makes good records important. Also, the obligor's professional or driver's license may be suspended for failure to pay.