Quality rotors are inexpensive. Replacement every time is simple, adds 15 minutes to each corner. I also find for my style of driving and towing new rotors mated to fresh pads gives me better stopping power and longevity over longer intervals.
So since it’s cheap and easy why not if it’s better overall.
Any extra stopping ability is slight but you can notice more when towing.
Very little to no difference if the old rotors are turned because this gives you just as good of a surface as a brand new rotor but as I mentioned before most of the time, rotors can't be turned anyway. At least this is my experience but this is when the rotors and pads have had many many miles together. People who change their brakes at 30 or 40 thousand on they still have supposed to have pad left should be able to turn the rotors. My theory is there was no point in taking them apart in the first place.
So, vs just slapping a new set of pads on old somewhat grooved rotors, putting new rotors on with a new pads well normally give at least a slightly improved feeling.
I will also say they when you have older rotors and put new pads on the braking will actually get better in just a few days.
But either way you go, your vehicle should be able to be safely stopped no problems.