Like Bronco said...It is generally a good idea to change wires every 100k miles. Also, the general rule of thumb for cap and rotor is about every 20-30k miles. IF you run a hotter ignition (hotter coil, MSD, etc) you'll usually have to replace the cap and rotor about every 10-20k miles. My last cap and rotor lasted about 15k before it started having problems.
Slade