No, we're concerned that it might go shorter than 12 months.
It works for science journals. You can go shorter in some sciences, but in social sciences and humanities, and I was just doing some research on this, the 20 most used articles in one of the journals I am involved with were published between 1992 and 2009. That's where you're getting the most use, so 12 months isn't really a lot of protection, and we rely on the good graces of the libraries to continue to subscribe to the latest.