Think of it this way for sake of discussion. Let's say a plug is good for "x" number of sparks. It may be possible that the number of sparks, (sparks per mile?) is greater when offroading in high range than when driving at 70 mph down the freeway. If so, then the total number of sparks (x) is reached with less miles driven...seems like you would have to do an awful lot of low speed/high rpm off road work to really make a difference though...and, a plug does not fail after exactly "x" number of sparks.
08 JK 23S - Colorado Jeep Club No. 204
Too much to list - see my profile for details on build
16 JK Rubi with all the trimmings
NRA Life member
"It takes a special kind of stupid to believe criminals will follow gun laws."
I do not consider myself a smartass. I point out the obvious, search for the truth, and speak fluent sarcasm. I am, by experience, an accomplished curmudgeon.