Once you have created a large range of materials and textures, it stands to reason that you could possibly use them in more than one blendfile or production. This may save you a lot of time in not having to recreate things you have already successfully created.
You may also be able to use a previously created material or texture as a basis for a new one. Fortunately, Blender provides some very useful tools to make this possible.
You will need access to a blendfile that has materials created. Why not use one that you saved from a previous recipe? We will not be modifying this blendfile, merely using or appending some of its materials into a new scene we will create. For the purpose of illustration, I have appended materials from the Creating a realistic copper material recipe from Chapter 2. The specific file is copper-turret-04.blend
. You can use whatever blendfile you have access to.