If the frequency of changes to requirements is very high (almost daily), which of the following life-cycle models might make most sense?

When considering a life-cycle model for a situation where the frequency of changes to requirements is very high, the Lean model is particularly well-suited. Lean principles emphasize minimizing waste and increasing efficiency, which aligns perfectly with the need to adapt quickly to changing requirements.

The Lean model encourages a focus on delivering value to the customer by prioritizing work that contributes to that value and being flexible in how that work is executed. This adaptability allows teams to respond swiftly to new information or changes in customer needs without being bogged down by extensive planning or rigid processes.

In contrast, other models may not be as effective in situations with high variability in requirements. For instance, Scrum, while Agile and iterative, has fixed timeframes (sprints), which may limit how frequently feedback can be integrated into the development process. Continuous delivery Agile enables frequent releases but may also involve components that rely on a more stable backlog. Lastly, the Waterfall model is not conducive to environments with frequent requirement changes, as it is structured in a linear fashion and assumes a level of stability in requirements that does not align with high variability.

Therefore, in the context of rapidly changing requirements, the Lean model provides the necessary flexibility and focus on value delivery, making it the most sensible choice.