Well, I declare right now I'm not planning any impairment for some decades yet. It's funny how what we expect, we so often get - good and bad.
Bottom line is, if I find I can't remember things, and/or I stop making sense (stop the smart Alex remarks at the back NOW), I'll just have to odeal with it, but I'm not going to plan my life on it. Not one single one of us knows when tomorrow might just not come, so I intend to get on with my life, having adventures, doing things I never envisaged I would and generally creating havoc.
I'd rather regret having done somethng bonkers, rather than forego the experience because of something that might or might not happen. I've had a great life so far and intend to have much, much more of the same.
I'll pay attention to the things I can ultimately control, and laugh in the face of the things I can't. Life's to short to plan in mediocrity.