Remember our graph for first-time buyers?
Does the relationship look similar for customers after a second purchase? You tell me.
Across the board, response is higher. But the relationship is very similar. The "anniversary bump" is now at months 10/11/12 instead of just at month 12, but the relationship is very similar.
I could keep showing you these images for 3rd/4th/5th purchases. No need. This is the relationship. Your mileage will vary, but not by a lot. I just ran the relationship for customers purchasing for a ninth time - same deal.
Again - I ask you, given how you market to customers today, you likely don't act upon this information (catalogers could via print). But if you could start over, knowing what you know here, how would you change what you are doing to account for the inflection points identified above?