I am at 60k on the odometer with 8 years on the calendar and lately have been taking care of replacing drive belt, hoses, t-stat, coolant, fuel filter, and air filter.

I'm getting close to 20 mpg around town and the car runs really smooth, but I haven't had it from the beginning so nothing to compare with. I am wondering about the plugs. Am I at a point where they should be changed for PM reasons or no need? Better mpg is always nice.

Jaguar doesn't change 'em at 60k, or so my dealer says. 100k seems like a long time for plugs.