I guess the answer would be very subjective...is your sparkplugs still new and/ or clean? If they are...then you don't need to change them...But the best is to change them so you get the performance you desire.
If you're running on an EFI system, then high tension plugs OR wires do not give a significant performance improvement - with EFI systems, the optimum amount of everything (including air and fuel) in the combustion chamber is already computed by the ECU.
If you're running on performance carbs and forced induction (turbo/supercharger), then it may provide some improved performance. Might as well slap on a performance ignition coil (Nology, Mallory, MSD, etc.) to get the most out of it. One combination I saw was torquemaster plugs with splitfire wires. Splitfires are prone to miss if not gapped properly; while there's absolutely no gapping with torquemasters .