Seven years. Four years of slow growth and minimal profit, followed by three years of rapid growth and more work than I could handle by myself. I have since moved into doing design work and run a business that manufactures commercial wood products now. I still do a small amount of custom and one-off work, but prefer the structure and stability of the commercial side now even with the narrow margins.
My path was based on patience. I started with very little capital and reinvested everything back. There are some great lessons to be learned from getting by with very little. Learning where and how to spend money is make or break in a lot of cases, I managed to stay free of debt entirely even if it was a bit painful.
My advice, work on developing processes not products in the first years. These are great years to learn, develop ideas, understand the market, etc. Creating a tool or process is what will give you a competitive advantage or a name. Once you get behind on orders there just isn't the time so those slow years were a godsend looking back.