Rules of Thumb are great... And there’s no no substitute for demoing gear. But if there are some objective shortcuts based on science (psychoacoustics) that we might all benefit from, well that’s what I’m leaning into here.
The criteria in the initial post, I had hoped would help highlight some areas where differences are beyond subjective. Perhaps they’re a little too broad. While absolutes are hard to come by, certain other criteria should be fairly easy to measure/experience.
For example (2) cables with the exact connectors, the same, length, with the same shielding, braiding, etc. but different gauges. Shouldn’t the thicker gauge produce a better sound in the majority of systems? Many manufacturer’s have this exact set up, and we’re simply selecting one gauge/price over another based on our budget. I would think at some point the differences become negligible, say between 12 gauge and 10 gauge (again on the majority of systems). At what point can most humans differentiate between the two (say 18 to 16, 18 to 12...)? Knowing this we might all be able to save a little money and spend it elsewhere in our rig.