It also depends on the individual and how much change they are willing to take on. In my business life I'm always in a constant change, always reinventing myself, improving how I would and be more efficient at what I do. I enjoy taking on new challenges, it keeps the spice in life. At almost 60, I cannot begin to count the many changes I've gone through in my business career even though many times I resisted change it always worked for the best.
Changes in my personal life though? Drastic enough to start over? I think for me it would be harder to do now but not impossible. As mentioned before, it would depend on the situation.