- Baseline 30-day repeat rate ≈ 14% (from your last 90 days of orders)
- Redemption occurs on next visit; no stacking with active promotions
- Contribution margin on next order ≥ 35%
- Randomized holdout on 20% of eligible first-time buyers
- Measurement window: 30 days from first purchase
- Primary KPI: incremental gross profit per exposed customer


