A With the increasing success of Quality Techniques such as Six Sigma, which show that quality perfection is a desirable objective, the old quality-cost trade-off as propagated by the Cost of Quality Models has to be re-examined. By scrutinizing the models' assumptions, we detect that they convey a rather limited and sometimes outdated perspective on quality improvement. By their nature they present static 'snapshots', yet neglect the dynamism of continuous improvement. Additionally, Cost of Quality Models are not adequate for determining an economically optimal quality level. We will show that this quality level indeed is at the point of perfection since we have to apply a profit instead of a cost perspective.