I hear the caps and rotors fail.
Caps and rotors are consumables in any situation.
Failures have happened across the board regardless of mfg. Cap and rotor replacement information can be seen below.
I recommend the KD Rotors over the Bosch as it has a tighter fit on the shaft. Other rotors have worked loose causing much damage. By the same token the KD Rotor fits tight so some mistakenly think it is fully seated when it is not. Clearance between the bottom of the rotor and the magnetic disc is about 1/2 mm.
Please note - Keep the spring clips tight on the cap they often get bent out of shape by manhandling them.
You should always inspect the carbon button inside the cap to make sure it is there and properly aligned with the receiving hole.
As for rotors failing the problem usually exists with running CDI and or coils whose resistance is too low like .75 ohm etc. Stay away from square coils. Always run 1 ohm or higher. That is why I recommend either the Bosch Red (1.8 ohm) or Bosch Blue (3.4 ohm).