For a few years, beginning 1973, the WTS started saying a lot about the role of ones conscience in making everyday, personal decisions.
This was firstly introduced at the elders schools that were (and probably still are?) periodically conducted at the branch offices. I can recall a newly-appointed Circuit Overseer in 1973, straight out of Gilead and quite horrified that people were asking the elders for guidance about matters were (to quote) "up to ones conscience". Then, either late in 1974 or early 1975, there were a series of articles in The Watchtower that dealt at length on this matter. These articles came over as quite definite that it was not "The Society's" (or the congregation's) role to impose anything that resembled a Talmud when it came to personal matters - including dress and grooming.
Scuttlebutt has since had it that this was done, looking ahead to the "Tribulation" - which of course, was about to happen "at any moment". After all, every bloody fool new that the Great Tribulation was no longer "just around the corner". No, instead we were now staring down the home straight at the thing! (Apparently). Story has it that the WTS was preparing the congregations for the "persecution" that was to follow, in which we would be cut off from Brooklyn - and likely from the local branch office, too. All this would make it impossible to ask "The Organisation" for guidance, so it was important instead to have a well developed "conscience" to make these calls for us. So the story has it after the event. I don't know if it really happened that way, or if it is just another product of the Great JW Rumour Mill !
Anyway, all this about the matter of conscience (whether spoken or written) was interpreted differently from congregation to congregation. Some took an approach that was noticeably more relaxed. One congegation in Australia (Newmarket, in Queensland) became quite renowned for this. A number of the ministerial servants wore beards, jackets or suit coats were not required wear a the book studies, and - unbelievably, women were permitted to wear pants suits, both at the hall and while out in field service.
In mid-1977, the new circuit overseer (those in Australia may remember "Cyclone Rex" Mainwaring?) nearly blew a gasket when he saw the line-up of bearded ministerial servants. However, the body of elders got its way, and no action was taken against those brothers. They retained both their beards and their positions!
However, a few years down the track, the Governing Body realised what a genie it had released from the bottle when those articles about conscience were published. By the early 1980s, things had reverted to the legalistic regime of beforehand.