This spring the AME who looks after my plane showed me the badly cracked exhaust system of another plane that had been brought in for a pre-purchase inspection. It had just gone through an annual a couple months before by a different shop and it was very obvious that the other shop just pencil whipped it, at least judging by the exhaust and a couple of other items that were almost as life threatening. Big cracks that kill don't just suddenly happen, they start small and grow over time.