I think the clearest line between rich and not is whether you have to work to earn a living. In my book, if you're an "earner" at all, you're not rich yet.

I think it's both not working to earn a living and what a person can easily afford to do.

I say this because I don't think one needs a lot of money to not need to earn a living.

Sure, whether you need to work to earn a living depends on the standard of living and risk level you're comfortable with. But I think it's possible to set a reasonable upper bound. Say, around the point where your interest income at a typical risk-free rate, after reinvestment to keep pace with inflation, would put you among the highest earners in the world if it were ordinary income. Defining "highest earners" as those in the top two US tax brackets, that amount is currently around $8-10M, or on the order of 2^23 present-day dollars.

Personally I think on the order of 2^22 dollars reasonably qualifies as well. Maybe that's because of the standard of living I'm used to. Certainly if you have 2^24 dollars and you don't think you're rich, you have a definition of wealth that ignores a major qualitative difference in what a person can afford to do. Above 2^23 dollars, I think additional wealth begins to put you more in the realm of the low-level aristocracy and rulers than the merely rich.

That's just begging the question -- if your income is in the top 1% of all earners, and you still "have to work for a living", then you're pretty clearly not living within your means.

It's quite obvious that the definition of the word "rich" is relative, and subjectively defined. Yet everyone seems to focus on that relativity as if it's some huge, meaningful insight. It isn't. At the end of the day, if you're earning more than 99% of everyone around you, and you still can't pay your bills? That means that you're doing it wrong.

Some people hurt for cash and are frugal no matter how rich they are. This helps them get rich.

I don't think its a matter of "hurting for cash." Its the thought that you could lose it all just as easily as gaining it all (or actually much, much easier). And as you get older and accumulate responsibilities, the overhead of families, good schools, retirement, all weigh on you making that thought all the more horrific.

Entrepreneurs are probably much more vulnerable to these kinds of worries, because that's what they worried about (losing it all) on the way up.

Well that goes to the definition of rich. I'd say it is (or should be) at least partially to do with the psychology.