Visualizing as early as possible helps ground conversations. Sketching gets the juices flowing and helps drive convergence. Continued by an organic progression of linking screens together and documenting thoughts.
How far the linked screens/prototype are taken depends on the project, team and audience. Time should not be the deciding factor since there are many tools and many creative shortcuts.
5 Axis's of FidelityIt’s dangerous to automatically assume a b/w wireframe is sufficient for all projects. Each project needs to be assessed on a sliding scale on 5 axis’s of fidelity: Visual, Interaction, Data, Breath and Depth.
Quick IterationsDesign is not done in a single pass. It takes many iterations. The more you do upfront, the less you have to do in the back-end.
VisualizingThere is clear need to convert business requirement words to screens. But there is also a great advantage to visualizing the interaction and actually clicking through the flow.
Think It ThroughThe larger the application, the more difficult it is to hold it all in your head. Walking through the prototype helps you find those unknown or procrastinated pages.
