> I know a couple of men in their 50s, one is relatively wealthy (some tens of millions of dollars), and I have often seen him on top of a machine with a wrench

> I know a couple of men in their 50s, one is relatively wealthy (some tens of millions of dollars), and I have often seen him on top of a machine with a wrench in his hand at 6am. Sometimes it's 3am. He starts a new company every year or two and adds it to his holdings. He owns farms and factories, and runs all of them personally. (it baffles me that he has enough time) I know another man who's relatively broke (owns his house, not much else) and says he is too old to try any new ventures. I suspect a large reason for their wealth disparity is their attitude disparity. Or perhaps energy disparity? The guy who serially starts companies and works from 3am in the morning is probably in the 99th percentile in terms of raw energy available to him.