Release bearing noise

Just wondering has anyone had multiple issues with their release bearing squeaking. I have replaced mine 3 times for noise since I have owned the car. Have replaced 2 with in about a year. I'm using ford parts?? What could be going on? It has started to squeal again when your off the clutch. The last replacement was in June 2010 and only about 4-5 K miles ago.

Any input will be appreciated.
 
what type of grease are using during install? other causes can be worn pivot ball or fork, damaged fork, worn/grooved bearing retainer, bad input shaft bearing in the tranny to name a few. I haven't replaced any other during a clutch change. I use long life grease that I got from a Ford tech and doesn't wear away like most other grease we would tend to use, don't know if that is the saving garce or not but he advised be on it ( another project) so I tried it and seems to be some good stuff.

Motorcraft® Greases