You can create an Event for that customer. The date would be 6 months in the future, then check the box to Display in Action Items ( to notify you) before or after the event date. This is not attached to the invoice, so you may want to reference the invoice number in the notes. 

I would suggest adding ACT! CRM   It would allow you to report on the service and follow up calls.   It now integrates seamlessly with Sage 50 when you add a S50 Data connection.

Please call us if you would like more information on this program.    304-810-4526  - Allen Byard is our ACT! Certified Consultant that can explain more about the features of the program.

Shirley Byard, Best Business Strategies  304-233-2612  [email protected]