throwout bearing

I've repalced my slave cylinder and throwout bearing three times in the last four years. The last time was only about four months ago. the throwout bearing keeps going out. Any help?

Is the bearing binding up?
How do the fingers on the diaphram spring look?

As the noise is getting worse, now i'm thinking its the pilot bearing.How hard is it to change the transmission shaft that goes into the pilot bearing?Just in case its damaged?

The input shaft for the trans is expensive and difficult to replace (requiring special tools).
Does your clutch ever fail to disengage? The pilot bearing can lock onto the trans input shaft and negate the clutch.
Are you sure you're on the right track or could there be another bearing going bad?

My '97 started making a god-awful grinding when I pushed in the clutch...my first thought was the throw out bearing. I took it to a local reputable shop ony to find out that my pilot bearing had crapped out, thus destroying my input shaft. Long story short...$1500, one new pilot bearing, input shaft, clutch and trow out bearing later and I was up and running again. This happened last year.. now I am experiencing shifting problems (hard throw). Sometimes really hard to shift into 2nd and 4th. I believe that I let it go too long and damaged my gears. To sum everything up... have them changed NOW!