how do rotors get “uneven” and calipers"Sticky", w/signs of “overheating” on an '89 corolla-?-when 10,000 miles ago at a different repair shop–the front brakes were: “relined”, rotors “replaced”, the system supposedly flushed and i was also charged $35 for an “anti-rattle spring kit”(what’s that?) ?? i paid $290 for that job and the current repair shop wants $5-600 to redo the fronts!! I should add that I live on a hill & so the brakes are used possibly more than those on the flats. The current estimate of up to $600 sounds way out there–thanks for any clarification/help!