Two points..... How much quality built in at the design stage has been done? You design quality in at the early stage as, in the long run, it is a better AND cheaper way. Costs of correction can escalate due to later changes, remedial work ( recalls etc) and brand image and confidence. There can be arguments between engineers and accountants. One wants engineering excellence and the other reduced costs. Where is the balance? I remember in my metallurgy days, we had to tip 150t of molten steel out of a ladle onto the floor in the casting bay The nozzle for casting was blocked. I discovered the refractories manager changed the lining to a cheaper one. It reacted to form a high melting point aluminium oxide instead of low one. The solids blocked the nozzle. He was lucky to keep his job for not checking for potential problems.
