Not true. EPR engines do not have a longer lifespan. The hole EPR/N1 argument is accademmic, it is just different ways of indicating thrust. Epr is the relationship between Ram velocity (Pt2) and core Exhaust velocity (Pt7), in short, how much does the engine accellerate the air. But since almost all engines today are highbypass engines, and threfor 70%-80% of the thrust comes from the fan air, using EPR is just as much an assumption as using N1.
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