We're at 1140hrs, 1200 hours due soon obviously and the a/c went into service in Jan '03.
I'll have to check with Maintenance but I'm almost certain that we've not had anything on the plugs except possibly some of the usual tiny post-production stuff in the early hours after entry into service.
We lost an inverter in the first week, a screen after two months and a main gear actuator after a year, all replaced on warranty of course. Other than that, it's been a case of throw fuel into it, light it up and leave.
Although we always run heavy, tanking fuel where there are no passengers due to local supply limitations, we're pretty rigid about the loading and, despite the nod and the wink as well as the Italian shrug of the shoulders, 2850 means 2850 for us.
The last oil analysis showed nothing but we're increasing the frequency anyway to six months which, for us mean about 120 hours. Maybe we should be doing it more? I don't know, I just wish they'd give us a plug that works.