During the push to make converts pre-1975, jws were told to drop a bible student that did make progress in 6 months, to drop them and go on to another person who might make progress;
Kingdom Ministry February 1970 p.4
● How should we go about terminating unfruitful Bible studies?
This is a question that we ought to consider if any of our present studies have been in progress for approximately six months. Are they coming to the congregation meetings as yet, and are they beginning to make their lives over in harmony with what they have learned from God’s Word? If so, we want to continue to help them. But, if not, it may be that we could accomplish more good with our time by using it to witness to others.