As a company we never want to be sending out emails or any type of communication for that matter, that crosses that line of too many times. So how many is too many? That's a difficult number to pin down. It depends on many different variables and those variables can change from company to company. What we do know is that a gentle reminder can help spur a thought and/or lead to a sale without be intrusive. A gentle reminder could be a salesperson casually mentioning a sale without trying to "close the deal". It could also look like a reminder on an invoice or statement. However it's done, remember that, as Henry Ford once said, "a business that makes nothing but money is a poor business."