I've been at this job for almost ten years, and I don't think there was a head of HR that was there for more than two (and it's not just the head, it's everyone, most of them being around for less than a year). It's not my department and I haven't had any issues with them, but it's always made me wonder. The whole point of HR is, theoretically, to smooth things over between employees and management, but clearly something is amiss.