Quality is defined by the “norme ISO 9000:2000” as "the aptitude of a whole of intrinsic characteristics to meet requirements". It exists only through the judgement of the user. This judgement is based on many criteria which, for some, can be evaluated objectively while others very subjectively. In this definition, which is very general and applicable to any type of industry, it is advisable to clearly determine the whole of the expressed or implicit requirements. The first error being to restrict them with the final customer. Indeed quality no longer fits into one client relationship – the supplier.