This article is from the RCA SelectaVision VideoDisc FAQ, by firstname.lastname@example.org (Tom Howe) with numerous contributions by others.
RCA tests indicate an expected life of about 1,000 hours play time for
the diamond stylus cartridge. Some early reviews of the CED system
stated 200 hours of play time, but this was for the sapphire stylus,
which was never used in a production player. There are a couple of
conditions to watch out for that can result in immediate failure of the
stylus cartridge. One is the attempt to play a cracked disc, since the
crack can rip the stylus arm right out of the cartridge. To avoid this,
I always inspect my discs for damage when I first get them. The other
condition is a static discharge between the stylus and disc surface that
can actually destroy the conductivity of the titanium electrode on the
trailing edge of the diamond tip. This is a rather unlikely occurrence,
but can happen with some players if the grounding spring near the top
center of the turntable is broken or missing.