I didn't learn about Cash Flow until I had screwed up often enough that the lessons became obvious. With a little bit of luck, you might escape that experience by modeling your firm after this infographic. Too often we architects operate on positive cash flow and think we are profitable; but the slightest change in that cash flow stream will rock the boat, often capsizing it.
Here it is - Sustainable Cash Flow for Architects
The smaller the firm, the harder it is to follow this model because overhead expenses can easily grow faster than billable hours and those increases in expenses represent a larger change in your overhead factor.
Note that paying off the initial investment creates the opportunity for more growth. Also note that increases in overhead expenses creates a brake on growth by reducing or eliminating profit.