Apple has acknowledged that a small percentage of iPhone 5 models have sleep/wake buttons that fail to work intermittently. This only affects iPhone 5 models manufactured through March 2013, and does not include iPhone 5s or 5c models.

Apple has created a repair extension program that will cover the cost of repair of faulty iPhone 5 sleep/wake buttons, even if the iPhone is out of warranty. Complete details are available at: https://ssl.apple.com/support/iphone5-sleepwakebutton