stronbl

If you track your car or drive it very spirited and utilize the brakes significantly, the friction between pads and disc will generate a lot of heat, and I mean a lot of heat. Then the components cool down, and then heat up again ... repeat over a period of time necessary to wear out pads and/or discs and you introduce the potential of fatigue. At some point in time the caliper pins, caliper bolts (I would recommend replacing these too - they can get more expensive as you need two per caliper), and perhaps even the cotter pins could fail. Replacing them when you do the work is just added insurance you have fresh metal with appropriate strength properties. One could probably do it every other cycle if their brake and disc usage was light city driving, but as noted these are relatively cheap parts, so it's also cheap insurance.

And regarding the caliper bolts, if they have not been replaced and have been subjected to a number of heat-cool cycles, then they could be seized and quite difficult to remove. Another good reason to replace them regularly and use an anti-seize compound too.

Chrono

Good thread to read through.

Couple of things to stock up on for this job that you might not already own:

A breaker bar for loosening the rotor bolt.

An impact screwdriver for the Phillips screws on the face of the disk that "locate" the rotors.

A pad spreader OR shims to drive the pistons back.

A decent center punch of the proper size to knock out the retaining pin. Don't try screwdrivers and old round files like I did!

Anti-seize compound.

Ags 911

The caliper on the 09 C2 does not have a center pin to punch out. I did a complete brake job (rotors, pads, sensors, and brake bleed) 6 months ago on my 09 C2 coupe. You have to remove the caliper to remove pads from the underside instead of the top on a S model. Huge difference in time and complexity... Sensors should be replaced along with caliper bolts. It took me all day for all 4!! S models can be done in less than half the time. Saved a lot of money though!!! Bought parts from pelican and parts geek. Right at $850 for all parts and fluid. Good luck!!!

Chrono

OK so it's just the S with the pin.

I think the OP has long since done his job, so this has become more of a meandering brake parts thead.
Other tip: The spring and cotter pin are generally on eBay for less than $10. It's a Carlson part.