I see some rust on the tire on the front driver's side of the 99 Ranger
XLT 4X4, and got to looking under the front and see that the  Front
Stabilizer Bar Link (as the Chilton Manual calls it - it connects the
stabilizer bar to the lower control arm) had broken at the top and there
is maybe an inch gap where there should be bolt.  

Fortunately my local Ford dealer had the 3 parts I needed and it is now
repaired and back to new - and I see a difference in stability when
cornering or turning.  Only $34.00 for the parts, which I deem
reasonable.

Question is that this seemed to surprise the parts guy, and yet they had
the 3 parts in the kit in stock.  Is this a common failure?  Or what?  
Relative to where the parts had been for the past decade, and the
corrosive materials splashed on them, the repair went very well.  But I
am curious about the why of the break.  If it was a fluke that is OK,
but if this was an indication of an alignment problem then it is time to
get worried.

The passenger side link seems to be OK; it was just the driver's side
one.

Any clues?

HR.