When the pads are under 4 milimeters in thickness.
that depends on how often you drive. best way to determine if brakes need changing, is to look at brake fluid resevoir. if level is low, your linings are worn and either need replacing or renewing
No.
No you dont need to bleed the brakes if you are just changing the pads, there are more ansers to car maintenance questions at ; www.carbasics.co.uk
No
No you don't, the front and rear brakes are independent of one another. -Sean Ford Mechanic Riverside,CA
Yes, you do.
Bleed brakes after changing pads to extract any air bobbles.
yes that is if they look old and rusty to
Only if pressure is not firming up.
YOU ONLY BLEED BRAKES WHEN YOU DISCONECT ANY BRAKE LINES OR HOSES OR IF YOU CHANGING YOUR ENTIRE FLUID. IF YOU JUST CHANGE PADS AND OR SHOES YOU DO NOT NEED TO BLEED IT. JUST MAKE SURE THAT WHEN YOU PUSH THE PISTON BACK ON YOUR CALIPERS, THE RESERVOIR CAP MUST BE OFF TO AVOID DAMAGING ANY COMPONENTS.
pad brakes are disc brakes, it's known as changing brake pads for disc setup and changing brake shoes with drum brake setup.
They need replaced when they wear out.