I was under the impression that we were talking about Obama's taxplan for rich plumbers, making more than 250,000 USD, so my badPug wrote:
The scale is purposefully vague for a reason - it's subjective. "Enough disposable income" and debt management have to do with your lifestyle.
So...how much do YOU have to earn to have disposable income out the wazzoo and little or no debt = rich.
When I started as a young lawyer - trainee I was probably -1: no income and all debt.
Hard work (Lowing would be proud of me), a fair bit of luck and some tax evasive techniques earned me better living: probably 7.
Health issues during recent years cut me back to probably 4 (hail to the European health care system, but I still haven't found a government's tit to suck on).
Next month I'll start working as a DA, so I'll be 8 again. I still drive a jag and ride a beemer.