@strech, FWIW I've been using the same cord for some years now.. but I'm really conscious about not letting it get twisted up or kinked up anywhere.. The cord is way longer than I need, so I spooled it up and twist-tied it to keep it short.. I pick-up and put-down my log the same way every time (establishing ritual tends to be a big part of vaping for me, YMMV), and it still seems just like it was when I got it..
High heat for extended periods, could also be a factor.. although, I've left my UD running hot for long periods w/ this cord, and it still is fine..
Lately I've been keeping it at lower temps w/ the VVPS when not in use, like low nylon stem temps, and I start by dry ripping a long GonG at those temps w/o stirring, until flavor is gone, and then I stir it well, turn up the temperature to GonG temps, and finish it through a bubbler.. and repeat!
I only dry rip until I need to stir these days.. I'm too sensitive to particles to do it any other way.
@CurryLeafTreehugger, I never use rusty screens personally, and I'd recommend against it.. but I've had the same thing happen to screens and ELB's from really long ISO soaks..