Keep any Awake! bound volumes you find for the years 1968, 1969, 1970, 1971, 1972.
These are the years when the year 1975 was heavily being promoted and articles were published containing statements that many JWs today deny were ever made by the Watchtower.
For example, in the late 1960s, the Awake published an article that say flat out that it was a "fact" that Armageddon (the end of this old world) would come about before a young person could finish college and start a career.
It is important to be able to document statements like that.
--VM44