An efficient acquisition model uses the gross profit from a new customer's very first transaction to fund the acquisition of the next customer. This transforms customer payments into a direct, self-perpetuating marketing budget, enabling growth without external capital by playing with "house money."
Lifetime Value (LTV) is a vanity metric; Lifetime Gross Profit (LTGP) represents the actual cash available to reinvest in growth after covering fulfillment costs. All acquisition models and payback calculations should be based on gross profit, not revenue, to reflect true capital efficiency and growth potential.
By engineering your model so that the gross profit from a new customer in their first 30 days exceeds your acquisition cost (CAC), you can fund marketing on an interest-free credit card. The customer's own payment repays the debt before interest accrues, creating a self-funding growth loop.
Shortening the payback period from three months to one doesn't just triple the speed; it compounds growth. A one-month cycle allows for reinvesting capital three times in a quarter (8x growth), while a three-month cycle only allows one reinvestment (2x growth), creating a 4x difference in potential.