at my work place, we never turn rotors. ever.
the reason why it is recommended to replace at the same time is because manufacturers do not put super thick rotors on normal vehicles to save on weight which equals better handling and fuel economy. it's not like the old days where they just put a solid thick disc on your car...
they are designed to wear at an even rate, together.
can you get away with doing the pads only? maybe. i personally wouldn't. trying to save a little money can end up costing you more in labor afterwards. especially when you're talking about brakes.
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