Whilst researching, I found several sites that suggested DC generators required much more maintenance than AC generators. From what I can tell these sites seem to have assumed that the AC generator was brushless while the DC generator had brushes. So it would make sense that the DC generator would require more servicing in this scenario.
However, I'm still wondering if there is any truth to this, is there some other factor that results in DC generators having a shorter lifespan than AC generators?
The sites in question: