During the product design stage it makes good sense to re-use previous design knowledge wherever possible. This may seem to be a bit of a lazy option but is valid for the following reasons:-

1) The existing design will have been fully validated and tested.

2) Considerable time and effort will be saved instead of  “re-inventing the wheel”

3) The existing design layout and supporting documentation already exists.

This doesn’t mean that innovation should stop, on the contrary any improvements in design should be incorporated into the new version.

Product design is an evolutionary process which makes best use of previous innovation.