I am 40 and I do not currently plan on retiring. I still put money into retirement for my spouse, but as for me, I think that when I lose the ability or simply the willpower for continued productivity that there is simply no point anymore. I refuse to be a pressure on the earth's ecology if I cannot aid in the development of the world in the interest of posterity and their well being. My last huzzah will hopefully be meaningful use of my corpse for scientific purposes, or even my live body should it be allowed at that point.