This is a post by Dave Martin on PTC site.
Everybody wants to get to market faster and keep costs down. That’s why it makes sense to reuse as much of your existing design data as possible. When you can update CAD files from a current product, previous product, or just common components, your work gets out the door faster, and that can lead to significant savings.
Unfortunately, engineers, designers, and managers often make decisions that prevent data from being leveraged. So it’s not easy to simply make a few changes to last year’s model, even when the part or assembly design seems to be exactly what you need.