2011 (when I hired on): you absolutely may not work from home, both because we don't want you to, and because the customer says you can't
(time passes)
2012: Boss: "Uh, you can work on that document over the weekend. We'll come into the office together."
2013: Boss: "Uh, you can work on that document over the weekend." Me: "How can I do that if I can't work from home?" Boss: "... You can use your own computer, but DON'T TELL ANYONE!"
2014: You can casually work on some of your normal assignments from home as long as they don't require resources on the network.