To determine whether you need to create a deployment model, ask yourself this: if you knew nothing about the system and someone asked you to install it and/or maintain and support it, would you want a description of how the parts of the system fit together? When I ask this question of the project teams I work with, we almost always decide to develop some form of deployment model. More important, practice has shown that deployment modeling is well worth it. Deployment models force you to think about important deployment issues long before you must deliver the actual system.