Have you read the saddle fitting thread(s)? Start there.
From what you said, I'd guess that your needs in the cut-out department have changed. Your sitbone width won't change, and although we really haven't identified a good test for saddle shape, I wouldn't think that that would change much, either. But the soft parts, as you say, do change size and shape over the years.
Does your current saddle have a cut-out? What saddle(s) have you ridden without problems in the past?
Speed comes from what you put behind you. - Judi Ketteler