Software development life cycle (SDLC) can be applied to different project management methodologies – with some differences, of course. In Waterfall, for instance, you finish one phase and then start the next one. This approach includes gradual execution of every stage completely. In Agile, on the contrary, we divide the project into sprints and apply SDLC phases to each sprint. After every development iteration, the client is able to see the result and understand if they are satisfied with it or not.