Material, parts, products, etc. must be adequately identified from receipt and all the way through the system. This is generally easier to do than it sounds. Most of the time (I stress MOST), the system already in place for identifying things (by batches, serial numbers, part numbers, bar codes, whatever) is adequate and needs only to be documented. What gets people into trouble with ISO 9000 is that often the identification is "understood" but not explicit -- that is, people "know" the identity of things sitting around the production area, but there are no tags, labels, signs, etc. identifying those things.

Remember, this applies only to products and to the parts, components, materials, etc. that go into products. It does not apply to such nonproduct things as coffee makers, pop machines, wastebaskets, etc.

Traceability is not mandatory -- it's "where it is a specified requirement," either because you make it one, or your customer makes it one. Generally assessors expect to see a traceability system where such is necessary to product the customer or for problem solving purposes. Again, in MOST cases, if traceability is necessary, you already have it, and all that's necessary is to document how it's done.