that's hard to really pinpoint.
i pretty much fell out by 2007/8 and stopped attending meetings, but it was a slide well before then as my meeting attendance and all of that was pretty spotty from 2004 until then. that whole period was so f'ing awful i've blocked a lot out.
i remember telling the elders at the hall i grew up in on the week of my birthday that i was turning 18 before the watchtower meeting so they needed to transfer my cards to the hall i planned on going to because that was the last day i was going to their hall. by that time, they knew how i was being treated so it wasn't on bad terms with the elders that i spoke with as they aren't all demonized monsters. some are really nice, just unfortunately trapped in a cult