When a device comes back from a customer, you have a choice: repair or replace. For most disposable-style products, repair isn't worth it. The cost of labor and parts usually exceeds the price of a new unit. And if you're dealing with a sealed device, opening it can void any warranty and create liability.

Instead, have a clear return policy that covers manufacturer defects. If the device fails within a reasonable period, replace it. If it's customer damage, that's a different conversation. But don't get into the habit of repairing things that are designed to be thrown away. It's not worth your time.