In 2 years, I've broken the driver's door lock cable 3 times.
Before I replace the cable again (easily a 2 hour operation), do you guys have any guesses as to what I'm doing wrong?

It works fine for a while, then it seems I have to pull the handle further and further away, until the door doesn't open or the cable snaps.

I wonder if the switch is flaky or maybe the lock mechanism needs to be greased to work smoother.

Thanks.

I have replaced this cable on both X300 and XJ40 cars
You need to lubricate the door lock. Just spray it with WD40 or similar to degrease the system
I then spray a 50/50 mix of SAE30 and mineral turpentine.as a lubricant.
Rough but it works.