I’ve seen startups get distracted by chasing the wrong type of revenue—for example, doing one-time licensing/custom development deals. While revenue is the first form of validation, retention is the ultimate form of validation. Furthermore, if you offer a one-time product, charge appropriately, and have good activation, revenue will take care of itself. Similarly, if you offer a subscription service and charge from day one and you have good retention, revenue will take care of itself.