Around 100000 km (60000 miles) it is highly recommended that spark plugs, spark plug wires, distributor cap and rotor be replaced; on distributor less ignition system just the spark plugs and the spark plug wires need to be replaced. The reason is that under the hood vehicle electrical components over time are exposed to moisture, oil, grease and temperature that can reach as high as 3-500 Celsius. As a result spark plug wires distributor cap and rotor, insulation break down creating an easier or alternative path to ground. Worn spark plugs also cause higher voltage requirements causing the ignition module and coil to produce higher voltage to overcome the resistance. The resulting higher voltage breaks down the spark plug wire's insulation, creating an easier path to ground. This cause the ignition module and coil to produce even more voltage, creating even higher current temperature within them.
Remember, higher resistance correlates to higher current temperatures and that electricity always tries to find the easiest path to ground. This higher than normal resistance weakens transistors and electrical insulation within module, coils and computers resulting in intermittent and premature failure. As a result you may experience a variety of drivability problems.
These problems are sometime hard to diagnose due to to the intermittent nature of electrical components as a result of temperature, heat and moisture; resulting in expensive diagnostic time. If you have already experienced an ignition module failure and have not replaced your spark plugs, (some late model cars have extra long life spark plugs in them, which could last 150000 kilometres. Consult your owner manual or ask as in person) spark plug wires, distributor cap and rotor, you most likely will experience the same problem soon. Maybe very soon.
Maintain your car regularly, precise and timely tune-up is ever so important with today's modern high tech engines and sophisticated automobiles.