The inevitable aging and depletion of components of a design object is an often overlooked topic that is addressed in this IEEE Spectrum article. Some excerpts I found relevant:
" At the very least, the quest for an obsolete part can escalate into an unexpected, budget-busting expense. Electronics obsolescence—also known as DMSMS, for diminishing manufacturing sources and material shortages—is a huge problem for designers who build systems that must last longer than the next cycle of technology. (...) The crux is that semiconductor manufacturers mainly answer the needs of the consumer electronics industry, whose products are rarely supported for more than four years. Dell lists notebook computer models in its catalog for about 18 months. This dynamic hurts designers with long lead times on products with even longer field lives, introducing materials, components, and processes that are incompatible with older ones. (...) The systems hit hardest by obsolescence are the ones that must perform nearly flawlessly. Technologies for mass transit, medicine, the military, air-traffic control, and power-grid management, to name a few, require long design and testing cycles, so they cannot go into operation soon after they are conceived."
Hence the existence of "company that provides obsolescence-related resources" such as Qinetiq Technology Extension Corp and the need to develop "tools to forecast and resolve obsolescence problems":
"To deal with that growing pile of unavailable supplies, engineers in charge of long-lasting systems must basically predict the future—they must learn to plan well in advance, and more carefully than ever before, for the day their equipment will start to fail. (...) Such companies as i2 Technologies, Qinetiq, Total Parts Plus, and PartMiner have produced commercial tools that forecast obsolescence by modeling a part's life cycle. To derive a forecast, the services weigh a product's technical attributes—for example, minimum feature size, logic family, number of gates, type of substrate, and type of process—to rank parts by their stages of maturity, from introduction through growth, maturity, decline, phase out, and obsolescence. (...) However, predicting when parts will become unavailable is still not enough information on which to build a business plan. "
Why do I blog this? curiosity towards this intriguing and overlooked problem.