~Making a courtesy call to your client prior to the invoice due date can be favorable to your collection efforts for a number of reasons including the following:

• It allows you to establish a solid working relationship with your client (a friendly call is always much nicer than a demand for money).
• After establishing a relationship with accounts payable, you can get valuable information such as - how often checks are cut and what their business practices are regarding payment of invoices.
  
• It allows you to ascertain receipt of the invoice
• Some businesses require "receiving" prior to payment of an invoice; you can make sure this has been done (or at least that it is in the process of being done).
• It will give you a good sense of cash flow issues prior to the invoice due date, which will allow you time to find out all you need to know (through web searches, press releases, or credit reports) prior to the invoice aging beyond recovery.