The methodology works whether the company features a predictable, subscription-driven revenue stream or a base of active customers who place discretionary orders. Companies that rely primarily on subscriptions tend to be easier to model because the key determinants of value are generally explicit. This includes Software as a service (SaaS) companies, and movie and music streaming businesses. The drivers for non-subscription companies can be more difficult to assess, such as customer retention, the pace of repeat purchases, and the size of orders.