After I unravelled two, I learned how to make the cable last years.
First - I take the motor itself apart and add CV grease to everything. Although this is not part of the cable problem, I figured "How often do I get to service the motor gear box anyway?" and just did it.
Then when I had pulled the old cables out, I found that the biggest problem was that the outer sleeve where it's factory glued to the squeeze clip that goes into the gearbox retainer - separates from the outer sleeve and the cable dies a short death.
I bough a new cable and using the same CV Joint grease, I pre-serviced it thoroughly.
Next I took some 60# sandpaper over the surface of the new sleeve to make it easy for glue to adhere to it.
Then I took just enough new 11/32" KV hose* - the rubber hose with the green stripe on it - to equal the length of the plastic sleeve and where it goes into the plastic lock device at least 1/4" or so - and split it lengthwise.
I then poured some Gorilla Urethane Glue into the rubber sleeve and slipped it over the plastic exterior of the new cable making sure that it goes over the retainer end too, for a half inch or so.
* True KV and CV hose has the green stripe and it's in 32nds of an inch ID.
I put the cable in place in the window mechanism to make it arc like it will be when it's installed - and then put another piece of split 15/32" PCV hose over the whole thing and clamped it together with a few screw hose clamps. I let it dry a day and I have had that running for the past seven years or so.
The problem I always have is that the end pops out the clip on the motor/gearbox end and the cable blows up.
Putting the extra hose over it with a strong glue is what makes it work for me.