Slave Cylinder Issue

Hello Everyone, I hope someone can help me. I have a 2002 X 4x4 with with 3.3 liter and a manual trans. I bought it about a year ago. since then it has chowed through 5 Clutch slave cylinders. I've tried different brands, different retailers, and even different driving methods. I grew up on a standard Trans so driving manual is no problem for me. I don't understand why they keep going out. they literally last from 1 month from install to maybe 3 months but they always go out. Please help. Whats wrong?