Who are your designs for? They can’t be for everyone. So, who are they for?
If they are for two groups of people, are those groups interchangeable with other groups?
Can you interchange your user base entirely and still maintain the integrity of the design?
Can you interchange pieces of the design for other pieces? One material for another. One detail or proportion for another?
Will your design work in multiple ecoregions? Multiple topographic settings? Multiple time zones? Multiple languages?
Does your design work, if the assumption upon which it is entirely based is interchanged with another? Are there multiple ways to concisely and
convincingly describe your design, in a language that we can all grasp?
Can you interchange who fulfills each role in the design process?
Can you interchange which craftsman or factory or construction team creates the work?
In all the great works of design, the answer to each of these questions is “no”. Make it “no” for your work as well.