1.1 DEFINITION OF OBSOLESCENCE
The English word obsolescence is derived from the Latin term obsolescere, which means “to go out of use or fashion.” The associated adjective obsolescent is derived from the Latin term obsoletus, meaning “worn out” (Baer and Wermke, 2000).
Obsolescence, as addressed in this book, refers to materials, parts, devices, software, services, and processes that become non-procurable from their original manufacturer or supplier. As parts become obsolete, users and customers are inevitably faced with a supply shortfall when their demands for the original part cannot be satisfied and no alternate parts are procurable (Atterbury, 2005; Rogokowski, 2007).
Generally, obsolescence is defined as the loss, or impending loss, of the manufacturers or suppliers of items or raw materials, as shown in Figure 1-1 (Tomczykowski, 2001).1 However, a more realistic working definition of obsolescence is when a part (material or technology) that is needed to manufacture or support a product or system is not available from existing stock or the original manufacturer of the part (material or technology).
There are many possible reasons for obsolescence. Some of the causes of obsolescence include the following: