I just met a sweet “charedi”, mainstream Jew wearing techeiles, so I asked him how it came about.
Listen to this:
He says he had the right strings sitting in his tallis bag for decades (!)*. He didn’t want to go against his rabbis. Then, one day, his chavrusa started wearing techeiles. So, he asks his chavrusa, what happened? And he learns that Rabbi Zalman Nechemya Goldberg himself wears techeiles. Enough for him. That same day, he learned how, went home, and retyed his tzitzis with techeiles! (Raavad)
(I was in an altered state of consciousness; unsure I got the story perfectly.)
* He gave a precise number, but it doesn’t make sense to me.