Pre-planning in 3d building is really, really important as you're finding out. When I build or create anything the first question I ask myself is, "How can I make this easy to change in my scene?" and then work accordingly. So, having "good" master shaders and groups that you duplicate is essential. There is a feature in the shaders worth checking out found in Complex -> Reference Shader. This allows you to create single shaders and then link them to many objects easily. So, when you change the master shader, all instances are updated. It's extremely useful when using procedural textures with the space set to Global. That way each instance of the shader looks unique but is actually the same shader! Mark