We know that the requirements frequently changed.
Some of the changes are inevitable due to changing needs and perceptions.
But many changes come because the requirements are not properly analyzed and not enough effort was expended to validate the requirements.
But SDLC-2013 is designed in such a way that the developer can focus on proper analyzation of requirements.
It is estimated 20% to 40% of total development effort in a software project is due to rework much of which occurs due to change in requirements.