Understanding CAC is vital to understand how cash efficient your SaaS business is and how successful it could be in the future. The simple math to build a profitable business is to make sure you make more money from customers in their lifetime than you spent in acquiring them. Lifetime is roughly the average number of years customers use your product for. CAC is a vital metric that often determines the marketing spend for companies. A clear picture of your CAC gives you a better perspective and helps you balance your spend and inches you towards profitability.