I was having heat creep related hot end clogs leading to skipped layers or plain old air printing (with extruder stepper skipping). Since I'd just received the all metal hot end I ordered a while back (Chinese knock-off, verified 2 mm heat break bore), I installed that and tried a print without changing settings.
Amazon Basics PLA, 200 °C at 0.4 mm nozzle, 50 mm/s (which gives walls and first layer at 25 mm/s), and 30% tri-hex infill -- and instead of clogging an hour an a half into the print, the new setup clogged after only about half an hour.
There is little retraction in this part -- every layer is continuous (that is, there are no travels between sections, only between infill lines and after layer end, it's a simple extruded shape from the first layer to the last), so I wouldn't expect excessive retraction to be a major issue.
Is this likely to be due to printing with the same settings I had for the original hot end? If so, what should I change (retraction, obviously, but temperature, print speed, etc.?).
EDIT: Reinstalling the previous (stock type) hot end after clearing filament material from the heat break has restored normal-seeming operation, at least when starting a print from cold. Parts are on the way to apply the PTFE fix.