Today electronic components technology evolves so rapidly that manufacturers have to upgrade their production equipment to produce the newer components. They then phase out their older equipment and then they cannot produce the older components. It is very probable that one or more of these components will be used on your ten year old circuits. You are then face with a serious problem that can be address in different ways.
Your first choice is to search for obsolete components stocked at various distributors and specialized resellers, in this case you may have to validate each component for their origin, functionality and quality to avoid counterfeit.
Your second choice is to replace the obsoleted component with a newer one but you may have then to modify your PCB layout to fit the new footprint.
If your circuit has many obsolescence issues it could be advantageous to redesign the entire circuit with today's components.
At Cysca-Sysacom we will help you at all stages of obsolescence, we can find and validate components, modify the PCB layout, redesign entire board with newer components.
We have redesign twenty years old board used in old industrial inverter and converter with today components. We've done the same for control board used by railroad industry.
Do not hesitate to call us we will help you to find a solution.