The ability to transfer the electrical impulse with the lowest possible level of resistances is the only purpose for the Oldsmobile Spark Plug Wires. Today the transfer of the electrical impulse from the ignition coil to the plugs through the spark plug wires is accomplished through glass fibers on the modern Oldsmobile.
With the level of efficiency at which the newer Oldsmobile engines are tuned too today, advancement in the ignition system along with a change in the materials being used, including the spark plug wires make the engines run with more power and better fuel mileage than ever before. This is why the older version copper core wires have been replaced by the glass fiber ones. The level of electrical resistance to the glass fibers is a significant improvement.
The owner no longer has to for the same reason the older cooper core wires did. What does have to be observed is the level of heat the Oldsmobile spark plug wires are now exposed too. Glass is a very viscous liquid. Like all liquids, they lose their moisture content when exposed to heat. When the glass fibers are continuously exposed to excessive heat levels, they dry out and become brittle. This causes them to crack which is why in time the level of resistance to the transfer of the electrical impulse to the spark plugs increases.
On or about the fifth tune-up, the glass fibers in the existing spark plug wires have been exposed to a sufficient level of heat that they should be replaced. This replacement of the spark plug wires should occur before the level of resistance to the electrical transfer of power from the coil to the spark plugs is sufficient to interfere with the performance of your Oldsmobile.