The core measures are the value a unit generates over its lifetime and the cost to acquire and serve it. In subscription businesses this often appears as lifetime value against customer acquisition cost, with payback period showing how quickly the cost is recovered.
Sound unit economics are the test a model must pass before scale is wise. If each unit loses money, growth multiplies the loss. If each unit earns a healthy margin, growth compounds it. Leaders examine unit economics to separate businesses that should scale from those that should first be fixed.