Life expectancy of Interconnects & Speaker Cable?

I would guess life expectancy of a well built cable to be around 100 years, give or take. Rough handling could decrease this time drastically.

I don't believe there has been any tremendous improvement in cable design in the last 5 years. The only 'improvement' that I find much more prevelant in today's top cables is cryogenic processing.
The designs are fairly similar. You could send your 5 year old state of the art cables out to be cryo'd, and I'm sure they'd be right at home with today's best cables.

Okay, now for a serious answer:

I'm a veteran audiophile and I still have some old Monster Interlink Reference (black) as well as a smattering of most other cables I've used over the last 20 years.

Properly terminated cables don't go bad under normal conditions. I just used a pair of those 20+ year old Monster Cables on a tuner in my reference system and they sound great. I doubt that they sounded much better, ever.

The main thing I have noticed over the years is that the resolution of audio cables has continually evolved. However, today, you can get top performance -- detail, dynamics, linearity, soundstaging, etc. for a small fraction of the price of the top-performing cables from 5 or 10 years ago.

Yes, the top prices of cables continues to climb, but so does the bang-for-the-buck in the moderate and lower price ranges.

Has it peaked? Well, probably not. No-one's using superconductors in the audio industry as far as I'm aware. Will future cables using superconductor technology sound better in your system? Very Likely. Will they cost a fortune when first introduced? Even more likely. Will it ever end? Not very likely...

Oops, I just remembered another likely scenario:

Optical cables and interfaces will become the new standard and our kids/grandkids will laugh at us when we tell them we used to use cables made out of real metal conductors in the old days...

Anybody that spent 5k on cables could undoubtably be convinced 5 years later that there was something infinitely better then for a tad more.

Believe it or not, I had my previous set of cables for over seven years. They were the Magnan Type Vi balanced, MIT Digital Reference, AudioQuest Sterling bi-wire speaker and Synergistic Research power cords for my Theta, Krell and Dunlavy set-up. I chose them after a massive search and auditioning period and was quite content because I could finally distinguish an instrument in a David & David song as being a guitar with the 50% silver speaker wire.

A year and a half ago I began another upgrade period and bought a Stereovox HDXV digital cable, along with a Conrad-Johnson D/A-3 DAC. That DAC being single-ended, I began another massive cable search and auditioning period that lasted three months.

I ended up, quite unexpectedly, with a complete recabling with Sonoran Plateau cables from Star Sound Technologies (www.audiopoints.com). They were only $500.00 a set for interconnects, digital, speaker and power cords, a lot cheaper than anything else I tried. The kicker came when I discovered as soon as I auditioned the Sonoran cables that my 'guitar' in the David & David song was clearly a synthesizer.

I have a feeling that I'll be dying with these still hooked up. The reason I say this is that even though they are copper and not silver, they are faster and clearer than anything else I tried, and I'm talking up to $2,000.00 a set cables. I'm hearing distinguishable instruments and tonal colors that I never heard before.

I think the secret is in the steel micro-bearing shielding, because you can lay the cables on top of each other and it doesn't affect them. They also seem to act consistently with any equipment, at least everything I've gotten through this upgrade. I went from Krell to Musical Fidelity to Herron, Theta to Musical Fidelity and Dunlavy to B&W Silver Signatures and everything is still fantastic with these cables. I even prefer and use the Sonoran copper speaker wires over the Kimber silver speaker cable that come with the Silver Signatures.

It's actually a good feeling to be so content and comfortable with the cables that I can think about upgrading equipment and adding a turntable and phono pre-amp, and not even consider the issue of cables.