I've had my Kindle 3 since they were first released in 2010, and it developed a hairline crack in late 2011 - roughly a year after I first purchased it. I've put my Kindle through hell and back since purchasing it (always keeping it in the official lighted case); I've dropped it in airports, sat on it a couple of times, had other bags thrown carelessly on top of my bag - containing the Kindle - during lectures, and I've used it for almost half of my total reading. The crack has not grown in any way between then and now, and my Kindle is still going strong.