alt Hacker Newsthere is a difference between the requirements changing and the poor quality, quickly made implementation proves to be inadequate.
agile approaches are based on the quick implementations, redone as needed.
my favorite life cycle: 1> Start with requirements identification for the entire system. 2> Pick a subset of requirements to implement and demonstrate (or deliver) to the customer. 3> Refine the requirements as needed. 4> go to 2
The key is you have an idea of overall system requirements and what is needed, in the end, for the software you are writing. Thus the re-factoring, and re-design due to things not included in the sprint do not occur. (or occur less)
This approach also accounts for the truism that "the customer doesn't know what they want until they don't see it in the final product".