Refactoring, yes... but I would include "refactoring" of both the design, and my understanding of the client's understanding of the design. And of the client's understanding of the problem. And my understanding of the client's understanding of the problem.

Hmm. I think what I'm trying to get at is simply that the system you end up implementing may bear little resemblence to the system you *thought* you were going to build :-)

(Why three? Just MHO. Seems to be enough iterations to get to the right design, without being too many to do in a reasonable time frame. <shrug>)