The costs of quality flaws vary according to the tardiness of their discovery

One of the obvious things it it useful to recal is that the later a quality flaw (defect) is discovert, the higher its cost. Indeed, the streamline of production or transformation process is a value adding process which increases raw material or product value at each step.
If the object of this transformation is to be discarded, all resources used until the very moment of its elimination will be wasted.

If defect detection occurs once the product left the plant, the costs will raise in accordance to the efforts spent to locate, return or replace it.
If additionnaly this product is already delivered to the customer, it is possible to face costs of penalties, a drop of customer confidence and a spoiling of company's reputation.