Hans, the job was fairly and unexpected simple (even for this novice). A couple of things that took me by surprise during the job which made it take longer that it should have and that you may benefit from.
If you are changing the rotors, the front caliper mounting brackets are held in with 10 mm Allen Key bolts (my largest was an 8 mm, so to the store I went). I also bough new caliper guide pins, but due to incorrectly reading the torque specs, I strip the new bolting and had to again headed to the store (thank God Auto Zone had them in stock). According to ALLDATA the correct to torque for the caliper holding brackets is 100 Nm (74 ft. lbs.) while the caliper guide pin torque is 34 Nm (25 ft. lbs.) on two-piston caliper and 27 Nm (20 ft. lbs.) on single-piston type, my S90 has the single piston type so it was 27 nm. And let me tell you, you don’t get any where need 100 nm on the guide pins before they strip.
After discounting for my multiple trips to the store for either tools or parts, the job took me around six to eight hours from wheels off the ground to tools put away. Along with the replacement of the pads and rotors, I also replace the parking / emergency brake shoes and holding springs. I took my time, and after the bolt stripping incident, I double checked all my torque settings.
Good luck, hope you have as much fun with this job as I did.