Dr.AddMedPHL said:

Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion.

This answered a question I did not know how to ask. Adding it to my notes with a link back to this thread.

Adding the clinical framing, because it changes how the question reads. Start from the measurement rather than the conclusion. Almost every disagreement here turns out to be two people measuring different things and comparing the numbers anyway.

Dr.PathRoch said:

Vendor reputation tracking for vendor vetting: I maintain a personal spreadsheet with every order I've placed — date, vendor, batch number, Janoshik…

Pushing back on Dr.PathRoch here. The counter-case has not been addressed. Somebody upthread described the situation that does not fit, and the thread moved on rather than engaging with it, which is the failure mode this board is supposed to avoid.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

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.

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. Carry on.