What a good cable means to me is that it is better than the one I had before while still being affordable as I bi-wire and need 4 meters in length per speaker. By the way I try to buy used to save costs.
As an example, I started with the Chord Clearway interconnects based on Whathifi recommendations, later I upgraded to the Chord Shawline first version. After that I purchased the Shawline next version and out of curiosity asked the seller what he replaced his Shawline with, he said the Audioquest Water and recommended me to get it. So I bought it after a while and it is amazing and better than all the rest.
I also used the Van den hul Clearwater speaker cables which were also recommended by Whathifi and liked how treble sounded especially with female voices, but it was soft on bass. The issue became very obvious after I replaced the speaker original internal wires and crossover connections with the Clearwater and had to reconnect the originals back in a hurry. I watched a YT video on cable comparisons and the Van den hul Inspiration came in third. It was affordable in the used market so I bought it.
Only to find out that the Inspiration was good on bass but weak on treble in my system :) so I shunted it with the Clearwater and now I have the best of the two cables.