I'm not old, but I probably look that way to most of you. I continually amaze myself with how many times I revise my view of the world around me, revise my view of how to fit me into that world, and revise the methods I employ to execute it in action. From my own experience, massive change seems to come in sudden hectic spurts, usually linked to majorly life altering events. However, constant change is at a steady rate, driven by my own sense of curiosity, competitiveness, and lack of complacency. As to learning, it is more difficult to learn certain things as you get older, like languages, but it has actually been easier to learn things like mathematics in my forties than it was in my teens. Probably because I know the value now, and can concentrate more on things that are value added to my goals. While it may be harder to memorize things now than when I was younger, I find that I draw a lot more actual application out of what I learn in a much shorter time period than before. So it's sort of a trade off--short term memory for long term synthesis.