A habit is a current, not an enemy
You cannot destroy a current; energy never simply vanishes. Fight it head-on and you are damming a river with your bare hands. The river always wins. So the monks never blocked it. They dug it a new path.
Read the idea ›In the modern view a bad habit is a flaw to be removed. The monastic view is almost the opposite: a habit is a flow of energy that found a channel. The energy is not the problem and it cannot be deleted. The only real move is to dig a new channel and let the current run there instead. Every method that follows is just a way of digging.
Stop asking “how do I stop this.” Ask “where else could this energy go,” and choose the new channel before you need it.