Excluding existing customers from acquisition campaigns avoids wasting budget on people who have already converted.
Exclusion Methods
Method 1: Customer List Exclusion
1. Upload your customer email/phone list as a Custom Audience
2. In your ad set targeting, add this audience as an Exclusion
Method 2: Pixel-Based Exclusion
1. Create a Custom Audience of people who completed a purchase (Purchase event)
2. Exclude this audience from prospecting campaigns
Method 3: Time-Based Exclusion
Exclude recent purchasers (e.g., last 30 days) but keep older customers in the pool if they might repurchase.
Best Practice
Maintain a regularly updated exclusion list, synced monthly at minimum. For high-volume businesses, consider automated syncing through Klaviyo or your CRM.