Err: variable " xxx " is assigned but its value is never used

 Hi ,
I have some condition onmy page to search the data. To set the conditions I set the Boolean variables for 8 conditions. My page works fine without errors. I am using that variable in my page.But, I will get this warning messages like assigned Never used. I am declaring & using everything in same method.
I tried by decalring those variables by Gloabally also. Even though I am getting this warning message. Why ?
 In the same method I declared local variables. Everything works fine. For one variable same warning message coming . Why ? How to get rid of this messages. ?? please respond to my post.
'The variable 'bCondition1Met' is assigned but its value is never used
The variable 'bCondition2Met' is assigned but its value is never used
The variable 'bCondition3Met' is assigned but its value is never used
 The variable 'bCondition4Met' is assigned but its value is never ...