Confirm there are not already settings or features that do what the shop is asking for: No

What does the shop want the product to do: Add a feature that enables customers to search their order history and quickly check if they have previously purchased a product, preventing duplicate purchases.

Why/how would it improve sales or efficiency: Implementing this solution effectively eliminates duplicate orders, creating a smoother purchasing experience for your buyers. At the same time, it drives long-term customer retention and builds brand loyalty by ensuring every transaction is seamless and reliable.