I had the clojuresque thought "I'm immutable" too... and it made me rethink this design choice: maybe I should version myself, to keep in mind that future me is also me!
Every year or two, I get a tattoo representing an idea or a defining point in my life. There are a few that aren't in line with the current me, but they're a permanent visual reminder of who used to live in this skin, so I love them just as much. Sort of real-life version tagging.