I only turn rotors when they are heavily grained/grooved have uneven pad build up, glazed or surface cracked.
I have gone from full thickness to well below minimum without turning on some vehicles and I'm older than Kevin...
Only turn as needed. Having them ground is even better, but I don't think we have a shop with a rotor grinder in Reno, much less most of CA. At one point, my grandfather's shop had the only disc grinder in N. CA and I have no idea where it ended up when he shut down his shop many years ago.
Grinding leaves them with that buttery smooth surface with swirls like they come from the factory.