Why Hood's geared turbines wore faster

Why did HMS Hood's Curtis-Brown geared steam turbines have a shorter service life than comparable Royal Navy Parsons machinery?

The Curtis-Brown installation extracted more power and ran hotter, increasing blade and high-pressure-steam stresses compared with longer-lived Parsons turbines.

The shorter machinery life followed from an efficient but demanding arrangement that circulated steam to extract more power than expected. Greater heat, pressure, and work increased wear on turbine blades and other components. Parsons machinery generally sacrificed some of that intensity for longer service life, demonstrating the engineering tradeoff between output and durability.