ok so i can hear my brakes on the front passenger side squeeking a little bit, i took the tire off and checked them and theres about 80% left of it.. why is it squeeking?

 

Are they performance brakes? If they are, you need to brake hard from 50 MPH ever so often. The audi dealer said it happens commonly with performance brakes or brakes not used that often. You might have dust build up aswell