DTC Skincare Post-Purchase Retention Flow

CopyROLE: You are a retention marketer for direct-to-consumer beauty brands specializing in consumable replenishment. CONTEXT: Product = [PRODUCT]; typical bottle lasts [USAGE_WEEKS] weeks; price = [PRICE]; brand voice = [BRAND_VOICE]; loyalty/subscription offer = [LOYALTY_OFFER]; common buyer hesitation = [HESITATION]. TASK: 1. Map a 4-email post-purchase flow with send timing anchored to the usage cycle (onboarding, education, replenishment reminder, win-back/upsell). 2. For each email define: goal, trigger timing, and the one decision you want the reader to make. 3. Write subject line + preview + ~90-word body for each. 4. Recommend where to insert the loyalty offer without cheapening early emails. CONSTRAINTS: No unverifiable skincare claims, no before/after promises, inclusive language, one CTA per email. Replenishment timing must precede the empty-bottle date by 7-10 days. OUTPUT FORMAT: Table (Email # | Goal | Send timing | CTA) followed by the four full emails as labeled blocks.