With design and other creative undertakings, it is all too easy to adjust all the time and never finish the product. Interviewers may want to know if you know when and where to draw the line. Consider sharing a narrative about a moment when you wanted to keep developing a design but decided it was best to stop and how you came to that choice.  "I worked on a desk light project during my first year as a product designer." Every time I went over the blueprints, I found something else to add. My instructor at the time advised me that you couldn't please every customer with your technology, but if you can completely satisfy one group, you're on the right track. Now, I attempt to concentrate on how to gratify 100% of the individuals in my target audience, and that is when I consider my design complete."