This one probably should have been stabilized years ago but was ignored, for whatever reason. Someone will inherit the job and will choose not to ignore it any longer. All the prior owners dodged the bullet. It is time to consider repairs now. I've had many clients make this statement to me a number of times. "This house is 25 years old. Surely it's moved all it's going to by now." The answer is "No." As long as it is here, it will move. It just doesn't have to move so much and so often. Stabilize it!