Dr.EM_Chicago said:

Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then…

Coming at Dr.EM_Chicago’s question from a different direction. The useful move here is to separate what is established from what is widely repeated. Those two sets overlap less than the confident tone of most write-ups suggests, and the second set is where nearly all the disagreement on this board comes from.

One concrete data point for the thread. Practical: whatever you change, write down the date and the reason. In three months the reason is what you will have forgotten, and the reason is what makes the record worth having.

One thing that is still open after Dr.EM_Chicago’s answer:

Was that from a primary source or from a summary of one?

stefan_berlin said:

Practical: whatever you change, write down the date and the reason.

Pushing back on stefan_berlin here. The objection nobody has made: this only works if the measurement is doing what we assume it is doing, and that assumption has not been tested here.

That is the short version; the long version is somebody else's post.

stefan_berlin said:

Practical: whatever you change, write down the date and the reason.

True, and it depends on a baseline nobody has stated. Without knowing where someone started, the same number can be an excellent result or a disappointing one.