In the past I replace the cap,rotor and plugs once a year just before the smog check and save the old cap and rotor just in case I brake one somewhere. Jacobs used to recomend autolite copper core plugs. havent noticed any differance between cheap and premium caps/rotors.

John

3 90 Trooper V-6's, 5 speed, 4.3L TBI, 31" BFG AT's, Fender Flairs, Bored intake, 1.6 roller rockers, MSD Coil, Jacobs Omni ignition. Heavy duty torsion bars, Rancho 9000 Shocks CAN'T SPELL, TO OLD TO LEARN, GOD BLESS YOU IF YOU CAN.