I might be trying to do too many things at once, but not noticing it! Now THAT worries me. ;) But seriously, I used to work as an engineer and I would keep a lot of complex information in my head at one time - a dynamic process simulation. As I approached the age of 40, I felt that I was less able to do that. On the other hand, with my experience in the business, I was being afforded opportunities here and there to move into more managerial roles. On the other other hand, I did not LIKE managerial roles. So I retired. Nowadays, I have a small farm. It is pretty complicated and lots of things to do; but it is simple in a way. With everything needing attention, you just pick one thing at random and do it - it is liberating to know I can never "catch up" and every single thing I do is "critical". Now that I am late-50's it isn't the mind that worries me so much as the body: pick-and-shovel work is better suited to the young, imho.