Component obsolescence (EOL)

Parts don't last forever. Manufacturers issue product discontinuance notices (PDNs) and product change notices (PCNs), commonly following JEDEC notification standards (J-STD-046 for changes, J-STD-048 for discontinuance), usually with a final order date for a last-time buy (LTB). After that you are buying from brokers (with counterfeit risk), redesigning, or retiring the product.

Products sold for many years, such as industrial, medical and building equipment, often outlive several of their components, and parts aimed at fast-moving consumer markets can have short production lives.

Mitigation: prefer parts with long-term availability commitments, check lifecycle status during design, subscribe to change notifications for your whole BOM, and keep the design modular enough to swap parts.