Hostas are tough! You can divide them any time the ground isn’t frozen but what kind of maintenance do they require? If you don’t like looking at the dead flower stem when it’s done blooming then just cut that back but other than that I leave mine alone until spring and usually don’t touch them at all. It depends on where they are. (I sometimes remove dead leaves in prominent places but otherwise I don’t bother. To keep it low maintenance I just chuck the stems around the plants. They are hidden