It depends. Sog is high yielding and you don't top at all, Scrog is also high yielding and you usually have to top it quite a bit. The end goal is just getting more budsites in an even canopy so they get more light. It also depends on light setup, a vertical setup and horizontal setup throw light differently.

Training, topping, sog, scrog, pruning are all just different techniques to direct the plants energy into making an appropriate canopy to make the best use of your light setup. Coli's are freakin cool.