In any of them either is OK, at least in terms of how natural it sounds. I wouldn't think twice about these, no matter the tense. Ordinarily the perfect would establish the time frame, but "by" already does that quite clearly. Using the perfect is somewhat redundant, at least to me.

Nevertheless, there is a slight difference. I think.
(Note that (17) should be simply "had filled", not "had been filled" (the latter sounds like someone filled it on purpose))

For example, in (18) vs (19), using the perfect sounds like the speaker is moving on to 1978. It sounds like she is moving on through what has happened in her life, giving a detailed description over time. Using the simple past sounds like she is talking about her marriage, then giving a time frame. Based on the fact that her story seems to not dwell on that time period, I think the regular past is a bit more natural. I expect some people might disagree with me, however.

I'm sorry I can't explain this very well. Honestly, it's hard for me to think of a situation where one is clearly wrong and the other right, and certainly I wouldn't think either to be weird in context.

I think the first of each pair (14, 16, and 18) sounds better. It's hard for me to explain why but I think Lyren's explanations are really good.

I agree with most of Lyren's comments, but there is an example right in (14) and (15) where the past perfect is clearly preferable: the phrase "that someone had bought before we ever moved into the house." This is an action completed before an explicitly stated past reference time. In the phrase "by two-thirty, hunger had gotten the best of us," the past reference time before which this happened is presumably "in the end" (at the end of the cleaning out process), so the use of the past perfect does make it a little more clear that the cleaning work continued after the break at two-thirty.

The difference between (16) and Lyren-san's corrected version of (17) is very slight; (16) emphasizes the state of the kitchen at the time "we" entered the house again; (17) emphasizes the fact that something was going on between the two times "we" entered the house.

(19) sounds awkward to me because of the combination of "by" and the vague time frame specified ("the following year"). It would sound better either with "by" omitted, which simply says that the marriage ended some time during that year, or with "the following year" replaced with some more specific time during that year. This is not a problem with (18), because the past perfect tense indicates that an exact time of the end of the marriage is not being given, and all that is important is that it happened some time during that year.

Thank you all!

Come to think of it, I should have added the continuation of the 14-15 pair.

(14') In the end, we had nothing left but a bag of onions, a bottle of cooking oil, and a packaged pie crust that someone had bought before we ever moved into the house ––– a stale remnant from the previous summer. L. and I held out all morning and into the afternoon, but by two-thirty hunger had gotten the better of us, and so we went to the kitchen to prepare our last meal. Given the paucity of elements we had to work with, an onion pie was the only dish that made sense.

(15') [Ditto], but by two-thirty hunger got the better of us, and so [Ditto]


Does this further context change your impression or judgment?