Why not kill yourself when you get too old to wash/feed yourself? I'm being serious. I've asked myself that many times and can't find a good reason why not.
It's not even about washing/feeding yourself. I simply don't want to have to work all my life. I'd like to spend my days reading, watching movies, traveling, eating out, etc.
To your question though, I find that as I get older life is increasingly more interesting. I suspect that will be the case regardless of whether I'm hobbled by my body.
Also, if I have grandchildren I can imagine wanting to hang around to see them grow up.
