Pruning. When is the right time to starg

Is there a certain height that would be recommended to start pruning or cropping the plants? How do you know when they are ready for that? Thanks.

4-5th node is typically when people start topping or LST.

You don’t really need to remove to much in early veg. If you are going to start LST, then once you decide how you are going to manipulate stems and branches you can just tuck larger fan leaves under.