Much better to think about low-quality products instead of defective. Junk can still be useful, and just good enough is definitionally good enough (most of the

Much better to think about low-quality products instead of defective. Junk can still be useful, and just good enough is definitionally good enough (most of the time). Also, most real engineering fields are full of projects that are done in non-repeatable ways and go horribly over budget. You're correct that for implementation you can get repeatable processes, but for process improvement you don't have anywhere near the level of repeatability.