According to S(h)antideva's Bodhicaryavatara, sometimes translated as Entering on the Path of Enlightenment, teaches, amongst its many teachings, that enlightenment is a path, that once taken, one does not get off.

The amount of time before the first instance of enlightenment from one's creation is a given set of time, variable for each. The period to the next moment of enlightenment is shorter, and so it goes, like a ratchet, moving us along the path, partially by our own volition and partially by just being on the path.

Have come to the conclusion that the periods of veering off, are merely the working out of all the possible permutations of the new teaching, till one gets it right. Not unlike Churchill's statement on America: "You can always trust America to do the right thing, but only after trying everything else."

The view of the path is beautiful, the walking of it, is the work. The Journey is everything, the goal is already achieved by starting it. Once one has a view of the path ahead, the view of the path behind vanishes, so one does not really have a sense of how far one has come, as much as how far one has to go, thus humility is built into the path and our practice.