Why Do Hard Drives Crash?
Hard drives are cheap. Manufacturers surf the curve between state-of-the-art design, reliability and production cost. They expect a certain percentage to fail within warranty, and offset this in the price. They cannot test every drive to destruction. Each drive is factory-tuned individually, and two drives manufactured in the same factory on the same day may turn out to have widely different life-spans. Bear in mind though – all hard drives are machines and all will fail eventually.