LACoS (Lifetime ACOS) and Lifetime TACOS are Sophie Society's methodology for measuring ad spend efficiency against a customer's repeat-purchase revenue, not just their first order. Because a customer's literal lifetime (80-90 years) is useless for payback math, LACoS bounds the calculation to a fixed window — e.g., one year — and asks what percentage of that window's revenue from a customer was consumed by ad spend.
Related to Customer Lifetime Value (LTV) as the Primary Amazon Margin Lever and calculated from data surfaced in Customer Loyalty Analytics (Brand Analytics Dashboard).
A custom spreadsheet (Sophie Society's) takes as inputs: repeat customer count/percentage, repeat units, and product price. It outputs: total customers, total units, average units per customer, and lifetime ACOS.
Repeat purchase rate, tracked over time in Brand Analytics, is used as an ongoing proxy for whether lifetime ACOS is improving — a rising repeat purchase rate signals improving lifetime economics without re-running the full calculation.
A brand can run a headline ACOS of 90-100% — normally a red flag — and still be sustainable if LACoS, calculated from actual repeat-purchase data via the LTV Calculation Spreadsheet (Back-Calculating LACoS), comes out much lower. The logic: the first sale is bought at a loss (or breakeven) on ads, but the repeat-purchase rate means a chunk of future revenue from that same customer arrives commission- and ad-cost-free.
Apply: Before flagging a high-ACOS campaign for cuts, check whether the product's repeat-purchase rate (via Consumer Behavior Analytics (Repeat Purchase Behavior Report)) justifies it — don't manage to the headline ACOS number alone.