Yes, it’s recommended to run multiple PMax campaigns if you have clearly different goals, like new customer acquisition vs. remarketing—but you need to structure them carefully, or yes, Google will blend everything by default.
Why Google Tends to Blend Audiences
By default, Performance Max campaigns are goal-based, not audience-based. That means:
Google’s algorithm uses signals (like past behavior, conversion intent) to reach your goal—regardless of your audience settings.
So if you don’t explicitly tell it who you want to prioritize, it might mix cold traffic with warm leads in the same campaign.
When to Separate Campaigns
You should run separate PMax campaigns when:
You have different bidding strategies (e.g., Maximize Conversions vs. Target ROAS).
You want to control budgets separately (e.g., don’t want remarketing to hog spend).
You’re testing different creative angles (warm vs. cold users need different messages).
You’ve set up new customer acquisition goals (with the “Customer Acquisition” setting enabled).
Pro Tips to Prevent Blending:
Use Customer Lists to exclude existing customers in your new customer campaign.
Leverage the Customer Acquisition setting in PMax (available under campaign settings).
Use audience signals wisely, but don’t rely on them alone—Google still explores beyond.
Bottom line:
If you lump everything into one PMax campaign, Google will blend users and optimize toward the easiest conversions—which might not align with your growth strategy. For better control and performance, splitting by goal (and managing exclusions) is the way to go.