Old manuals are sources of historical doctrine, procedures and techniques. They are often repositories of lost knowledge which can be reapplied, often saving people from having to 'reinvent the wheel'. Manuals in general are useful for many different types of people when properly read and used. Lost Knowledge Military manuals have short working life spans. Field manuals are usually replaced every ten years.
Technical manuals are in print as long as the army has the piece of equipment in inventory.
Then they are thrown away. The military like the rest of the modern world has a tendency to believe that new is always better. In my experience, after paying attention to them for over thirty-five years, this is not often true. Reinventing the Wheel Often when a new manual is written, it conforms more to the current fashions and fads of the time when it is written. Many pieces of information are declared not necessary, because they do not fit in current doctrine and are deleted.