Who else is using old cables/interconnects, and is happy?

Although I have changed my system substantially in recent years, I still retain both speaker cables and interconnects that I have owned for ~15 years. I use Audience Au24E speaker cables and RCA interconnects, and a Virtual Dynamic David XLR between my DAC and integrated amp.

The system sounds very good, and I am not inclined to make any changes to the cables. Having said that, though, if anyone has used similar cables and found big steps forward without breaking the bank, I'd be interested to read about your experiences.

More broadly, I would enjoy hearing about cables that other members have stuck with for years.
^^ Only if they are second or third hand and broken in!
If you have the money, do some research (very hit & miss) and then try some new cables. Morrow Audio makes some very nice sounding cables, and many of their lines are competitively priced. 

The key with system changes like this is to replace all of the cables in your signal path (or at least your most important signal path) and then just listen to music over time. Don't try hard to hear any immediate differences. If you do, fine, but you'll still want to live with them for a least a month-- over time you'll develop an opinion of what, if any, changes you're hearing-- after listening to lots of music, hopefully all of the kinds you normally listen to (and are familiar with).

Sometimes the change IS better, but probably, most often, you're not hearing "better" you are hearing "different". You decide if those differences are better, or are just subtle trade-offs that don't matter much to you. Unless the cables you're replacing are damaged, or are complete crap, you should expect some differences. Beyond that, it's up to you to decide if those differences add up to a real improvement that you feel is worth it. Or not. 

What is for certain true is that, above a certain level of build and materials, more money does not equal more quality. Period. Fact. It depends upon your ears and your particular system AND your room.
Haven’t found anything affordable to better my 20 year old BEL “the wire” speaker cables...
if I could find some cheap BEL interconnects I would pick them up as well.....
sdv0983, I used to have original Purist Aqueous. They were excellent when introduced. Colossus original, introduced later, was so much better, incomparable. I didn't try current Poseidon fluid or Aqueous Contego.

Monster Sigma are not too bad in some set ups but the rest I don't think so. They pass some signal, sure, but they can't really do singing.
I went through a system revision beginning two years ago. I bought a Purist Audio Design (PAD) Colossus silver balanced cable in the early nineties to connect my Wadia CD player directly to my Krell amp. It was a crazy move to spend 1200 on a single 1 meter cable in the 90s, but it was the only one that I tried from the cable company library that reveled the detail I wanted. Fast forward thirty years and I had three new cables checked out from the cable company and compared them to the old PAD. The synergistic Research won that shootout, but my wife and I were amazed how competitive the old cable was! There are great used items out there, you need to give them a listen.