Final answer:
The story 'Better Wait Till Martin Comes' creates suspense by having each new chair break when sat upon.
Step-by-step explanation:
The repeated plot element that creates suspense in 'Better Wait Till Martin Comes' is that each new chair breaks when sat upon. This creates anticipation and tension each time a character sits on a new chair, as the reader wonders whether it will break or not. The element of surprise and the escalating pattern of the chairs breaking contribute to the suspense of the story.