Having a suitable tool dedicated to software engineering (called a CASE tool, standing for Computer Assisted Software Engineering) enables analysts and engineers to stay organized and to keep requirements and design up-to-date. In a modern CASE tool, things you see on diagrams are only instances of visual representations of one or other model element. A requirement, a class or a connection is a set of data with a lot of valuable information behind, and only a few of those data is displayed in a view. In another view, you can display other data of the same model element. You can have a diagram detailing the attributes of a class and another putting it into context by displaying related classes. Change the name of the class, and the change will automatically and immediately be reflected in each view. Indicate a requirement affects another, and when requirements change, run a simple report to see what other requirements may be affected, and track down what elements of implementation may need reconsideration. Provide a detailed user scenario to your stakeholder to accept, and give it to your developer to implement and, finally, give it to your tester to make sure, the developer created what the customer wanted. And if a scenario changed, each relevant party will be kept up-to-date.