Not being a trained automotive technician I can only give you an opinion. I have been replacing my brake fluid on a variety of cars for years. Theoretically the only reason to replace the brake fluid is to eliminate the water from the brake fluid that builds up over time. Brake fluid, being hygroscopic, absorbs water from the air over time. This water will wreck the seals in the calibers and master cylinder and will decrease the boiling point of the brake fluid leading to decreased brake performance. Being a closed system if you have any gunk in the the brake fluid or system you have another problem that replacing the fluid won't handle.
I typically will take the wheel off of the corner of the car that is farthest from the master cylinder and will (with the help of an assistant) bleed the fluid out until the master cylinder is almost empty. I then refill the master cylinder with clean fluid and contine the bleeding operation until clear fluid comes out at the wheel cylinder. I will then do the remaining 3 cylinders until clear fluid runs, top off the master cylinder and I am done for a couple of years. It takes a little time but it is well worth it. Unless you are having other problems with the brakes there should be no need to disassemble any other components.
I understand that they make a one person vacuum bleeder gizmo but I have always just used a jar and a piece of clear tygon tubing. Make sure that you don't get the master cylinder level to low or you could get air into the system and you will be bleeding forever to get it out!!! I know.....
Hope that this helps.
1980 450Sl "Black Beauty"
2002 C230 Kompressor "Spicy"