How often does my 1991 oldsmobile custom cruiser need a tune up?

DO A TUNE UP AT 30000 MILES. BACK IN 80S AND EARLY 90S YOU DONT HAVE 100000 MILES PLATINUM PLUGS AND 100000 MILES DEX COOL ORANGE ANTI FREEZE. THE GREEN. ETHYLENE GLYCOL ANTI FREEZE HAD TO BE CHANGE EVERY TWO YEARS. SOME OF THE 91 CARS HAD DISTRIBUTOR CAPS AND ROTORS DONT LAST LONG LIKE THE DISTRIBUTORLESS IGNITION SYSTEM. THATS WHY YOU HAD TO DO A COMPLETE TUNE UP AT 30000 MILES.