Saw my buddy at the shop always fighting brake squeal. He used to guess the pad clearance. Got a lot of comebacks, people saying brakes still noisy. Then he bought a cheap feeler gauge set. Started checking every rotor. Callbacks basically vanished after that.
@oscarh16, that bit about callbacks vanishing after using a feeler gauge is so true. It reminds me of when I kept hearing squeaks from my truck's suspension and just tightened things by feel. The noise always came back until I borrowed a torque wrench and followed the actual specs. Suddenly, no more weird sounds. It's like your buddy found out, sometimes you just need the right tool to stop guessing. Cheap tools can really save your bacon.