I was taught that the purpose of a tiny hole in the back was more
for the purpose of being able to remove the stone while you are
fabricating the piece yourself. I have seen a lot of Native American
turquoise jewelry, and others, where there is no pinhole and the
backs looked much cleaner and nicer to me without it. I guess I
didn't even consider the possibility of the hole being used down the
road if a repair was needed, but I guess it makes sense.
When I was shown the trick of using the really thin tape type of
dental floss to remove a stone during the fabrication process, I
stopped using a pinhole so I could have a really clean backing. I
supposed if I were to be concerned that the connections were fragile
and may need repair in years to come I might consider using a pinhole
again, but mostly I would just make sure that my connections could
withstand the test of time & wear.
(I don't mean that to sound harsh and if it reads that way I am
sorry. Sometimes words on paper can come off differently than you
wanted to express, just because they lack the tone of voice you would
use when speaking.)
I just mean to really consider whether a design can withstand wear
and time, but I don't design with future repairs in mind. (Does that
sound any less snobby?
Hope this helps, it's just my opinion.