NEW DISCS TAKE LONGER TO BED IN
Fully bedding new pads to decent condition worn discs/rotors may take only 200-300 miles but when new discs are fitted at the same time bed in times to achieve outer to inner edge contact (full width blue-grey contact band as mentioned under point 4 above) can be as long as 800-1000 miles due to extra components needed to be aligned to the vehicle. To Short cut this you can and EBC recommend should) have EVEN NEW DISCS Pro Cut Lathe aligned to your vehicle. This process removes only microns of new disc material and shortens bed in time by 75% of the time it COULD take giving you better brakes faster and avoiding hot spotting and pad glazing.
BADLY WORN DISCS/ROTORS CAN TAKE AN AGE TO BED IN
Discs/Rotors with more than 0.5 mm (0.020 inches) of lip at the outer edge or hollow in the centre of the braking area can take up to 2000 miles to bed in and will for sure cause Noise, brake fade,vibration and pad burning. Bad rotors can RUIN your pads. 95% of brake fade and noise complaints come from poor disc/rotor condition where the pads touch only at the outer and inner edges and have no chance to deliver an effective brake. Again new Discs/rotors is the solution or a Pro Cut on car Brake lathe realignment.