Hello Double_r,
Many commercial jet powerplants are leased, and are overhauled according to manufacturer determined schedules (barring overheats or vibration problems).
If I were you, I'd post this question in the 'Engineers & Technicians' forum also; you're more likely to get more specific information over there (maybe even put "Attn: Genghis" in the subject line; he'll know). Good luck!
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Patience is letting your motor idle when you feel like stripping your gears.