
Finding a defect at the factory means fixing it. Finding it in your own storeroom means a loss. That is why the product is inspected before it leaves the factory.
AQL sets the size of the sample drawn from the batch and the number of defects allowed before the shipment is rejected. Agree it with the supplier in the purchase order and do not leave it to judgement.
Write a ten point inspection checklist for your product, choose an AQL level, and decide who will inspect and when.