With password complexity and re-use rules spiraling wildly out of control from scatophagic companies trying to counter elusive security threats with non-specific blanket policies (War on Terror anyone?) the employees are being held hostage though managerial hysteria.
While its true that the best policy is password strength, forcing users to be unable to use the same password across multiple accounts (though in and of itself, also a good policy by minimizing the number of systems which could be accessed through a compromised password) through lengthy password recycle times and short aging policies, security actually becomes weakened because users are now starting to write them down. And not just average users - but professional IT staff as well! No one has as many systems which need to be accessed as we do - we hold the keys to the kingdom, and forcing us to write them down (albeit usually in some form of lightly encrypted means) seems to me a greater breach of security.