45 days since patch would mean plots will open up on Christmas. SE most likely won't give a degradation timer because it will lead to a lot of player conflict(stalking people's houses, etc). I believe that's why they didn't implement one in the first place. I mean, how annoying would it be to come back from a vacation to find a bunch of people constantly checking your placard to see if you've gone in just because you were gone for 7 to 14 days? Or sending rude tells to you over and over suggesting you just give up your plot so that people who "actually want it" can use it? That's exactly the type of thing that would happen.