My friendly catamaran dealer helped me make up my first replacement set - talk to Sawyer at Key Sailing. Much cheaper than going to West Marine. If you want to buy pre-made or custom stuff, Rick's shop (on this site) can fix you up quick.

I had a factory set of wires fail after two years. I think you can go longer if you do the fresh water rinse and keep an eye on it, espesh now that you know what to look for.