The aging schedule organizes invoices by their due date. It helps companies track who pays on time and what invoices are past their due date.nnA/R departments use the aging schedule to follow up with customers who went past the due date. Companies can customize the aging schedule to their preferred timeframe, but the most common aging schedules include the following:nnUnder 30 days.n1-30 days past due.n30-60 days past due.nMore than 90 days past due.