Please share your experiences with any or all of the above-mentioned milestones. The advice is all across the board: turn LO over/help LO sit/etc every single time, only help once or it becomes a game, don't help at all, blah blah.
What did you guys do? If your LO was previously a pretty good sleeper, was it a major setback? And how long was the disruption? If your LO was not a great sleeper to begin with, did you just sleep train at the same time? What milestone was the worst?