today's plugs can last 100k miles and a mc does no more harm than any automotive engine unless highly modified.
if anti-seize is used, one dot two threads up from the ground electrode. BG makes a mica based thread lube and it works really well.
the thing about anti-seize is most think a little does good but a whole lot is WAYYYYY better. some anti-seize will actually cause the seize to begin with especially so when it is too close to the combustion heat. that said, plug holes need to be cleaned out to prevent build up.

https://www.amazon.in/Anti-Seize-Com.../dp/B00H26S494

 

Using anti-seize causes over-torquing if not properly accounted for. It really isn't recommended for spark plugs anymore.

 

mc plugs are exposed to the elements more than automobiles so subject to corrosion, etc...even see folks here who showed some ugly looking spark plugs removed from living near salt water or washing with poor quality utility water..2 years or 30 K is reasonable as they state

 

hardie har har
internal combustion is internal combustion. i doubt that hd engine can come even near a turbo engine where cylinder pressures are WAYYYYY above what hd can come to.
the only thing i can think of that would be diff is that the hd engine that is air cooled will have a tendency to burn more oil, especially so when the miles mount.
plugs can FOOL a lot of people!!!! they replace the plugs and WHALA, runs like a scalded dog BUT the real issue is still there!!!!
new plugs fire at a lower voltage level and can mask other issues that WILL crop up later. the o-scope will tell all. typically plugs fire in the 8k range and as resistance grows from many sources, the voltage will rise till the coil can no longer support them, especially under load.
that said, many people think a 50k coil fires at 50k, NOT!!!!, still at 8k range but the margin to 50k is possible as resistance grows.
exotic fine wire plugs last a long time, but still subject to failure, had the set in rear cylinder short to shell after smoking two cagers, how fast?, clock stops at 120, so i do not know, but a 5k rpm, that clock is history anywho!
got to love that sport gear!

 

 

I'd wonder how tight that sucker was installed - possibly torqued way way way too high -

Someone commented that if you had taken out the plug yourself, you'd have had to pay to fix it yourself - probably true...

I like to think that working on my OWN sweet ride, I'd have never never never over-torqued it and it probably wouldn't have been a problem... I hate letting someone else wrench on my baby... At least if I screw up something, it's on me... and absolutely I admit I don't know everything, but I know I have a deep affection for my baby - something that I suspect most paid mechanics may not share - especially as my bike ages (22 years old now!)

 

Anti seize on spark plug threads. Always a lively topic, right up there with what type of oil do you use. winter is coming, lol.

 

Not everywhere...