Originally Posted by Dave Mayer

Wait:
So at our local Co-op, whereas replacing brake pads on road rim brakes is a simple task, taking 10 minutes and $10 per bike, in servicing most hydraulic disc brakes, we first need to ask: "Did you bring all of your parts?" If the answer is: "No", then we have to reply: "Do your research, and come back with your bleed kit, the correct hydraulic fluid, the correct pads, the right rotors, the right rotor bolts or lockring, and the right frame/caliper adaptors." Most just head right to a professional shop and brace themselves for a 2 week wait and a 3-figure bill.