Iterative prototyping helps designers refine their ideas and discover previously unknown issues and opportunities.  However, the time constraints of production schedules can discourage iteration in favor of realization.  Is this tradeoff prudent? This paper investigates if—under tight time constraints—iterating multiple times provides more benefit than a single iteration.  A between-subjects study manipulates participants' ability to iterate on a design task.  Participants in the iteration condition outperformed those in the non-iteration condition.  Participants with prior experience with the task performed better.  Notably, participants in the iteration condition without prior task experience performed as well as non-iterating participants with prior task experience.