Do speaker cables really make a difference ?

40.years ago Monster Cable provided dealers with an A/B cable switch for demonstration of their product with 16 GA lamp cable. At under a10 ft no one could reliably tell them apart. At 20 ft, Monster Cable became noticeably better. One customer brought in some (I think) Audioquest cables to compare. They were very different looking, but sounded no different. They were however 4X the cost of the MC. 0ne trick i learned was to coil the extra cable of a competitor - creating a series inductor and low pass filter making the system sound dull. The longer lengths also had higher resistance, negatively impacting the bass. As for patch cables, just use a good affordable cable and Deoxit. If youre worried about power cables and don't have a dedicated and conditioned 20A circuit and hospital grade outlets, you're kidding yourself. Even then, if the wire gauges are matched for a very high current load like a power amp, youre not apt to make any improvements or prevent any degradation. The amps power supply will handle momentary load demands. Finally, digital cables make no difference. They are binary (pun intended), they work or they don't.