Knowing When You're Done

As one lecturer I heard from Oxford said once:"The Oxford way is to begin at the beginning and go straight through to the end and then stop." That, of course, begs the question if you can't tell when you've reached the end.
The general rule when reading scripture is to accept the plain meaning if there is one and allow for a deeper meaning, possibly symbolic or figurative or metaphorical in addition to the plain meaning. If the plain meaning seems to make no sense (something we have to discern) then the meaning must lie in the other dimensions.
A second rule is that scripture, if it has God's authorship, is all of a piece. The pieces can't contradict each other without making God the author of error. Apparent contradictions therefore much imply that we don't understand what is being said.
Of course there is the other construction in the face of contradiction, that this is evidence that the material is not divinely revealed or that it contains errors. Now on the face of it, going back to what I said when setting out on this journey, we are all reading translations. So a contradiction may only be an error in translation. It may be simply an error in our understanding.
But the question before us is: How do we know when we are done?
The short answer and one that will satisfy for now is: We are done when we have achieved a stated understanding which is consistent with all the passages that we have considered. However, we are undone, i.e. we have to go back and review, if we find that subsequent passages contradict our prior understanding or expand it. Each advance in understanding broadens the reach of the light, but may also cast shadows back behind us which adumbrate what we thought earlier was understood.