A customer is a person or organization that has purchased from your store.
It is important to separate them from people who have not purchased yet. While you might treat them the same, they are merely prospective customers and cannot be measured as customers yet.
The vast majority of ecommerce customers are one-time customers who have only one order, while the rest are returning customers or repeat customers.
Eric Davis
How do your products determine customer behavior
In Repeat Customer Insights the Customer First Product analysis will measure customer behavior based on the products each customer first ordered.