Designing for the Life Cycle can be closely associated with economics.  This is very understandable when one considers the fact that the natural resources of the world are limited.  Therefore, the materials and natural effects of nature must be clearly understood and considered in order for the engineer to satisfy the concerns and requirements associated with the needs of the project he/she is designing.   The challenge is for the engineer to determine how the physical environment can be altered, or used to advantage, to create the maximum amount of useful product at the lowest possible cost.  In addition, the engineer should design with the idea of bettering the best.  To do this the design must account for tomorrow?s technology today.

The life cycle of a product or system begins with the identification of a need.  It subsequently extends through conceptual, preliminary and detailed design, as well as production and/or construction, installation, customer use, support, decline and disposal.  Simply put, the principal behind life-cycle engineering is that the entire life of the product should be considered in its original design.  An engineering design should not only transform a need into an idea that produces the desired product, but should ensure the design?s compatibility with related physical and functional requirements during manufacturing and operation.  This includes taking into account the life of the product (as measured by its performance), reliability, and maintainability. 

Life-cycle engineering goes beyond the life of the product itself.  It is simultaneously concerned with the parallel life of the manufacturing process and of the product service system.  In essence, there are actually three coordinated life cycles going on at the same time.  These parallel life cycles are initiated when the need for the product is first recognized.  During conceptual design, it follows that consideration should simultaneously be given to the product?s manufacture.  This begins the second life cycle, i.e., the creation of a manufacturing process including production planning, plant layout, equipment selection, process planning, and other similar activities.  The third life cycle should also be initiated at the preliminary design phase.  It involves the development of a service system for the product and a maintenance system for manufacturing.

Traditionally, engineers have focused mainly on the acquisition phase of the product?s life cycle. However, experience shows that in order to produce a successfully competitive product, performance and maintenance must also be considered at the time of the original design.  When too great an emphasis is placed on the engineering of a product?s primary function, side effects often occur.  These negative impacts often manifest themselves in problems dealing with operation.  Although sufficient specialized knowledge exists to solve many of these problems (Failure Modes and Effects Analysis, Root Cause Analysis, Reliability Centered Maintenance, etc.), this knowledge is most useful if it has been integrated into systematic solutions during the original design.