The Science of prognostic health monitoring of a system/product as it operates through out its designed operational life is very important and a massive operation.

If the product / system functionability is not understood, then the design functionality decay will slowly manifest and with poor detection result in a failure mode.

Prognostic health monitoring starts at the very first 'cut' of material in the component part manufacture, not as an after thought to appease regulatory body compliance.

Many issues exist in this mind set and over the years I hope to document and define these concerns I have, propose solutions and validate them with worked examples.