A one-time customer, also called a new customer, is a person or business who has only purchased once from your store.
They are important because they have shown the first behavior that makes them a customer. Before that time they were a visitor, prospective customer, or lead. All customers start out as one-time customers, a few might transition to a returning customer or repeat customer.
The vast majority of ecommerce customers are one-time customers.
Eric Davis
Analyze your customer's behaviors before they defect
Your customers aren't yours forever. Some might have defected today, never to be seen again.
You need to analyze your customer behavior so you can reach them before they defect.