Months to recover CAC: one of the best ways to look at the capital efficiency of your SaaS business is to look at how many months of revenue from a customer are required to recover your cost of acquiring that customer(CAC). In businesses such as banking and wireless carriers, where capital is cheap and abundant, they can afford a long payback period before they recover their investment to acquire a customer (typically greater than one year). In the startup world where capital is scarce and expensive, you will need to do better. My own rule says that startups need to recover their cost of customer acquisition in less than 12 months. (Note: there are other web sites and blogs that talk about the CAC ratio, with a complex formula to calculate it. This is effectively a more complicated way of saying the same thing. However I have found that most people cannot relate well to the notion of a CAC ratio, but they can easily relate to the idea of how many months of revenue it will take to recover their investment to acquire a customer. Hence my preference for the term Months to Recover CAC.) - www.forentrepreneurs.com