What is a significant disadvantage of the Waterfall SDLC method?

The significant disadvantage of the Waterfall SDLC method being time-consuming stems from its linear and sequential nature. In this approach, each phase of the development process must be completed before the next phase can begin. This means that if any issues or changes arise during the later stages, it can be quite challenging and time-consuming to go back and address those needs. Additionally, the rigid structure doesn't lend itself well to managing changes or unforeseen complications, leading to delays.

Moreover, once a phase is completed, going back to make revisions can require extensive rework and testing, which adds to the overall timeline of the project. This inflexibility can result in lengthy development cycles compared to more iterative methodologies that allow for parallel development and quicker adaptations based on ongoing feedback. Thus, the time-consuming nature of the Waterfall model is a critical disadvantage in fast-paced environments where adaptability and rapid deployment are essential.