Your sales system should indicate who has not ordered. Track the ordering habits of your customers (i.e. twice per week, once per month on the last day, on the 15th and last day, etc.) Run sales order reports and note all those who have not yet ordered now past their normal date. If possible, have IT create a notification report (you define the notice period) and have it run automatically every day as to who has not issued a regular purchase order to your company. Notify the appropriate sales personnel to make a stop, a reminding call or choose their own method to ask the buyer why no order? You want to know when a customer did not order as normal and be told this for all laggard customers on a regular basis. Maybe they just need an email reminder to be issued a week before the order normally is placed with your firm. Offer it to them if you think they would use it. Find out why your buyer is not selling and if he is perturbed about anything. If he is, find out what is it and what does the company need to do to resolve the problem? Do not wait and be surprised a customer has walked away from you.