I don't want to be so old that sex loses its appeal and the only thing to do while waiting to die is build entirely functionless trinkets that my grandkids will try to turn into bongs.
There's a little window, after you aren't getting laid but before it's been so long you get pissed off at the world, where you can just get shit done. Also, ritalin helps.
This guy should have won the Nobel Peace Prize. All nations could be finally united in our love for the wooden whirly-bird machine. Also, sweet Jesus that must take some serious forearm muscle to crank.