I replace plugs somewhat often like others, plug wires last forever, as do the coils.
Those are controlled by the ECU, no mechanical control for it, just as the others have said.
I have 267k on my engine, and just changed plug wires around ~240k.
Plugs whenever, people seem to have good luck with NGK plugs (ask around for the part #) albiet OE spec's a Bosch part.