Brake noise after pad replacement: what should an auto shop check first?

Brake noise after a pad replacement is one of those complaints that can make a shop look bad even when the brakes are technically working. The customer does not care that stopping distance is fine. They hear squeal, grind, or clicking and think the job was done wrong. I have learned not to answer that complaint from the counter without putting eyes on the car. First I want to know when it happens…