me and several of my friends have used WD-40 and PJ1
for years. its great and works well over the years.
My chain 13k, and its in great shape. but then agian keep in mind my tire is 13k also. and its not even that bad. my step dad (the guy i bought it from, he had it since new) road it like a 80 year old grandma.
so maybe that helped keep the chain, sproket, tire, etc in great shape.
i also clean and lube every 500 miles and i dont ride in the rain. that was the same way my step dad took care of it also.