Thanks for the infoThe schedule from the manual has you replace them like every 12k miles which is ridiculous. If yours are 21 years old I would say yes replace them, if you have put those miles on in the last year?
Pick a number between 3-5 yrs and one between 30k-50k miles and use it for your OEM plug changes, just do it on a consistent basis. And it never hurts to pull them in between to check for running condition and regapping.
The OEM IIRC does have a platinum tip.
Compared to MANY tasks on the plastic covered Wings...changing the spark plugs is pretty simple... There is only a few pieces of plastic to take off to get at them on each side....Umm which 1500 plugs is easy to do ? The oil drain plug perhaps .Flat 4 family I 'd call easy . Not so much on the 1500 . but thats kust my opinion .