High-end cables are a controversial subject, even among audiophiles. I know an extremely wealthy audiophile who uses cheap hardware store wire in his $200,000 hi-fi system. He thinks audiophile cables don't make a difference, so he doesn't use them. That's fine with me.
When I was a high-end audio salesman I sold a lot of very expensive wires to my customers, including customers that didn't initially believe cables would make any real difference in the sound of their hi-fis. "It's just wire" was the classic rebuke, I've heard it thousands of times. I'd offer my customers a choice of "free" wire or high-end cables for $500 or more. Some customers would just take the free cables and be done with it. But I'd get some doubters willing to try the expensive cables, with a promise that I'd return their money if they didn't hear a difference. I'd suggest starting with the good cables and live with them for two weeks, and then replace the expensive wires with the free ones. If they sounded the same, great, they'd get their money back. Only one out of four would bring back the expensive cables, and I think that best demonstrates my case. Even when people are motivated to return cables to get a refund, most did not. They heard enough of a difference to keep the expensive wires.
I do not recommend quickly switching back and forth between cheap and expensive cables, that mostly produces confusion, and "proves" there's no difference. The best way to determine the worth of the wire (or any upgrade) is to simply live with it for at least a week, then go back to your original gear. If at that point you don't hear a difference, don't buy the new cable. That's the bottom line: don't invest in better cables if you can't hear the difference.
I believe the right cables do make a difference, but before we go any further I have to concede that "better wire" probably wouldn't be the best way to spend your money if your hi-fi isn't pretty good to start with. Redirecting that $500 to better speakers, an amp, or turntable would provide a far better return on investment. If you're not an audiophile, I agree, investing in better cables isn't a smart move.
But once you have a well-matched, $4,000+ system, a $500 cable upgrade might be worth considering. I use XLO Signature 3 cables in my high-end system with my Magnepan 3.6 speakers, Parasound JC-2 preamp and Pass Labs XA100.5 power amps. The XLO cables produce a more precise soundstage, higher-definition bass, and sweeter treble than any other cables I've tried. I recently added AudioQuest Sky interconnect cables between my VPI Classic turntable and the preamplifier, and the AQ cable unleashed a significantly more holographic soundstage, with less background noise than any other cable. I use Zu Audio cables when I'm using Zu speakers in my system, the cable/speaker synergy brings out the best in the Zu speakers sound.
I'd love to hear from folks who have lived with expensive cables in the Comments section.