It is typical for aircraft generators to be run at a maximum of 8000 RPM. Of course, they operate at a lower RPM during cruise.
It is also typical for the generators to have an overhaul period of 1200 to 2000 hours. I have never seen one with a longer lifespan. However they will last longer, it is just that to prevent failure the short overhaul period was typical.
They are also commonly used as starter motors in addition to the generator duties. It would be really cool to setup a Lister with one of these as a starter/generator.
Chris