Most sparking plugs electrodes last a long time with the cleaner fuels nowadays. BUT, the big issue is external corrosion experienced in overhead twin cam engines like duratech, where plugs may need to be replaced after only a couple of years.

Doug
2011 Plus 4 in Rich Maroon

1972 750 “ComDom” sprinter
1958 Triton 650
1992 Triumph Trophy 900