Spyder7answered grow question 4 years ago The worst thing that can happen if you LST a plant too early is that you'll mangle the leaves and maybe dip them in soil, which will burn them from fertilizer/nutes. To reduce the risk, i think the general rule is 6-12" with 4-6 nodes. But in practice, the general consensus is the earlier the better, but that's about how big it needs to be for first timers; after you've done it, its like riding a bike and there's no real controversy: earlier is better (I started LST when my plant was 5" tall).
It isn't really controversial or complicated. Some growers add a twist like pruning the lowest leaf (or leaves) on the side that will be pulled toward the dirt and that can make LST'ing a short plant easier. Just pick a "how to" and follow it. Its very, very easy to do once you get the hang of it.