I agree with the above. But, when I have needed them I have always bought new rotors for all of my Cars and never had any issues with them.
Also, I did not have to buy Rotors for my Mercedes as I found 2 new ones in the trunk after buying the Car.

If you reuse the Rotors and do not have them machined you pads will not last as long and the can be noisy.

I agree with the better quaility Rotors to the extent that if you buy high quality Brake Pads you should have High Quality Rotors.

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84 300D, 82 Volvo 244Gl Diesel