Harold,

not exactly what you were looking for, but I once heard a business-management consultant speaking to a group of trainers (most working for others, some independent). He stressed the need to understand your cost of doing business, something I think independents can easily overlook.

(Meaning, something *I* can easily overlook...)

So you need to know your overhead, which for a person working from home could be the rent/mortgage, utilities, etc. (all fairly predictable); the typical cost of materials, supplies; the tax burden, etc.

He brought the point solidly home with this:

Suppose my margin works out to 25% -- after covering my expenses, taxes, insurance, I get to keep 25 cents on the dollar. Then, if I want to buy a $500 printer, I need to bring in not $500 worth of business, but $2,000.

This isn't to say "never lose sight of money," but rather "to make a choice, you need to know the facts."