The most cost effective and productive way to use a CFO is on a part-time basis.  Back in the day, Chief Financial Officers were called controllers and they would pay a lot of attention to monthly closings, financial statement preparation, and profit planning. With today's operating systems and more sophisticated accounting modules, CFOs can turn more of their attention to areas that are more productive to the business owner. 

For example, we can turn our  attention to business forecasting, inventory planning and reduction of risk. These aforementioned productive services do not take full time manpower. You can even add a number of others and it still will not require a full time CFO. 

When you hire on a part-time basis, they will not require benefits as most are independent contractors. These CFOs are also yours as long as you want to keep them. The Business Owner will not get a two week notice because they found another job.  The bottom line: CFOs who work on a part-time basis are more valuable because they will tackle the most important issues in your business and they are extremely cost effective.