Wear indicators??

Are there no wear indicators/squealers on these trucks? I thought I heard a noise, slight grounding noise, first time a few minutes ago. I'm not a professional mechanic but have done plenty of wrench turning so it put me under the truck looking to find were it was coming from. Sure enough, driver side rotor has just started a groove on the inside of the rotor. Never did have a squeak or any indication it was getting close. Hell, it still stops normal and doesn't "feal" any different in the pedal. I have 91,000 on it but, this is my first SD so I had nothing to go by. :dunno: Looks like I'll be changing some pads and rotors. Anyone have any info on some upgraded parts. I can't see going back stock if there is better to be had for just a little more. It's our nature, right?:nod: