most auto parts places are not turning rotors for customers any more. depends on area, there are many people that don't have a convenient place to have rotors turned. i've never seen it for less than $15 but still it's cheap and you definitely would like to keep the original, probably higher quality OEM rotor material over buying new.
144,000 miles on my 2001 before I pulled the original rotors and had them checked and what the machinist called more of a cleaning than a turning. Minor build up was what he called it.
Pads used were stock OEM pads changed about every 65,000 miles. Use? Car lived in San Francisco did daily Bay Area commutes and towed trailers through the sierras. Essentially your worst example of possible brake abuse.
The machinist who checked my rotors said that he almost never EVER sees subaru rotors that need replacing. Then pointed to a few other vehicle brand stock rotors and said that he gets lots of those and they need to be replaced. What were they?
GM products - Ford products and to my surprise some of the Honda products. Why? He said simple large heavy vehicles with under built rotors.
So far my gen 4 has been pretty much identical to my 2001 regarding pad wear. However around 32,000 miles when driving local slow speed streets with various stop signs and such the brakes would develop a terrible sounding grinding sound which would go away after a few higher speed freeway off ramp type stops where heavier use of the brakes took place. I actually pulled the calipers twice trying to sort out why they were doing this. Pads were fine and rotors were fine. Now at 43,000 miles this grind sound has gone away.
My suspicion is that the pad material had a slight consistency change and the dust it created at low temp light braking use caused this grinding type sound which was probably more like mini marbles rolling between the disk and the pad surface. Now with the pads worn down a little more this isn't happening so my suspicion is that the pad material that was generating this dust effect has been worn through and the material is generating dust that isn't causing this. Pads have about 50% left at 43,000 miles not all that different than my old subaru.
I'll be tossing on new pads probably OEM around 60-65K and the rotors are fine right now and probably will be perfectly fine at 65K. Since I started doing my own brakes ironically both and and the wife have had FAR FAR FAR fewer brake ie zero brake issues. Prior to that we seemed to have lots of odd early replacement of pads and oddly enough rotors which were no longer in spec ie had been turned down to the point they had to be replaced.
I caught a toyota dealer having turned down over 50% of the meat off my brand new rotors on my truck a couple of years ago. After I produced the receipt from their very own parts dept and the work order stating the rotors were new and not to turn them - then having the shop manager measure the rotors with me he finally caved and gave me in the box two new front rotors for my truck.
When shops turn your rotors and make it out as they are doing you a favor - it is a easy opportunity for them to trim down your rotors so your back for a full brake job sooner than later.