The LX450 is making a lovely grinding noise coming from the rear axle. I’ve identified it coming from the brakes and I’m looking to dig into it this weekend. Likely new pads- possibly rotors?

Essentially, my question is: Is it generally frowned upon to just pad-slap the rear? I know that technically the rotors should probably be turned with a new set of pads, but how much of a no-no is a pad-slap?

A set of OEM pads is a mere $58. I replaced these abour 38k miles ago- probably due for some fresh ones. New rotors are $100/ea for OEM- what’s a realistic cost to have them turned?