Obsolescence is a lack of availability of an item or raw material resulting from statutory and process changes, as well as new designs. Obsolescence deals with the process or condition by which a piece of equipment becomes no longer useful, or a form and function no longer is currently available for production or repair. Implementation of new technology causes older technology to become less supportable because of the diminished availability of parts and suppliers. 
Obsolescence management is the discipline that addresses obsolescence and Diminishing Manufacturing Sources and Material Shortages (DMSMS) as the service life of a product extends beyond the technology life cycle incorporated in the design. A Program Manager (PM) must address obsolescence throughout a product’s life cycle and plan ahead to make sure parts are available or new technology is available to replace those parts. The PM should develop a proactive approach to effectively resolve and mitigate obsolescence problems before they have an adverse impact on the Life-Cycle Cost (LCC) and system Availability.
The following are potential approaches the PM should consider: 
- Address Obsolescence management in the Request for Proposal (RFP)
- Review proposed parts lists for obsolescence
- Design features that facilitate change/insertion of new technology
- Establishing a rigorous change management process for life-cycle support.
- Using performance-based logistics contracts that provide significant latitude to manage technology refreshment. This includes ensuring they are incentivized to maintain currency with state-of-the-art technology and use readily available items to avoid the high cost of diminishing manufacturing sources and materiel shortages over the system’s life.
- Be proactive in the engineering design process prior to production
AcqLinks and References:
-  Website: ACQuipedia – Obsolescence Management
-  Defense Acquisition University (DAU) Glossary
- PBL Obsolescence Contract Clause Example