Killed mine by a silly mistake, I'd had it off the machine to test fit into a spindle mount I'd made for someone. When I replaced it didn't fasten a cable bracket and over a few weeks the cable flexing caused the wire to break inside the small crappy spindle connector causeing a big flash bang dead short. It killed the spindle instantly and blew a torque vector drive ABB ACS350. VFD faulted and wouldn't come out of reset.
The new spindle is much better 8.5A instead of 7A with a much larger better quality 4 wire connector so one can be grounded to body.

Yes I did strip it down heres some pics.
I was very pleased with the build quality and the bearings were in very good condition even after nearly 3yrs use.
Very easy to strip and I wouldn't hesitate to strip one down and replace the bearings. Basicly 30min job Max.