Replace just brake pads or rotors+pads?

If you have glazed your rotors from frequent granny-slow stops or break dragging, you might need new rotors if you want those pads to last or work well, glazed rotors doo a poor job of bedding in new pats. If you have a habit of hard breaking and then holding break pressure at the end while stopped, you can cause dissimilar hardness in the rotors metal grain structure, this will lead to pedal pulsing or rapid warpage while bedding in new pads. Turning the rotors won’t eliminate these hard spots.

So yes, it depends. On domestic cars where rotors are cheap, it’s great insurance to just get new rotors. I’ve been pretty lucky with just pad swaps though, but my driving style predicts this outcome. My wife is a granny stopper and break Dragger. Her Escalade developed a break squeal. A week of me driving it while on vacation cured the squeal.