Answer:
If the design has many layers or complex threading.
Explanation:
In most designs, we would assume that a specially made button that is very expensive would be a want. This is because fancy buttons generally perform the same jobs as regular buttons. However, an example of when this is not the case would be if a particular design has many different layers or very complex threading. In this case, the button might become a necessity, as it might work better than any other button.
