When auditing Meta advertising accounts for e-commerce brands, we frequently see media buyers struggle with the same fundamental questions: How many Ad Sets should actually go under a CBO campaign? And when launching new creatives, should you add them to an existing Ad Set or build a new one from scratch?

What advertisers traditionally call CBO (Campaign Budget Optimization) is officially known as Advantage+ Campaign Budget. Its core function is to distribute budget across different Ad Sets in real-time, directing spend toward the opportunities the system deems most likely to convert.

If your account structure relies on a 1-Campaign-to-1-Ad-Set-to-5-Ads setup, your CBO isn't actually doing much budget allocation because there is only one Ad Set. Instead, the real competition and distribution are happening at the ad delivery level among those five creatives.

This explains a common frustration: when you add new creatives to an existing Ad Set, the older, established creatives continue to hog the majority of the budget, leaving the new ads with little to no spend. This isn't a system glitch. Meta is not an even-split testing tool; its algorithm is designed to quickly favor creatives with the highest predicted performance rather than ensuring every ad gets equal delivery.

To scale successfully, performance marketers need to break down their account structure strategy into three key areas:

1. When Should You Split Ad Sets?

You should only segment your Ad Sets when there is a clear, strategic business reason to do so. Valid reasons for splitting include:

  • Targeting completely different geographic regions or countries.
  • Promoting entirely different product lines.
  • Targeting distinct audience segments that require unique messaging.
  • Optimizing for different conversion events.

If your target audiences, locations, and optimization events are highly similar, creating five or six identical Ad Sets will only lead to data fragmentation. Meta strongly recommends consolidating similar Ad Sets to pool budget and conversion signals, allowing the algorithm to exit the learning phase faster.

2. Where Should New Creatives Go?

When a mature campaign is performing stably, you can continuously introduce new creatives—but avoid bulk-uploading dozens of ads daily. If you dump 10 to 20 creatives into an Ad Set at once, your budget will be spread too thin, and the system won't be able to gather enough data to properly test any of them.

Instead, introduce a small batch of highly distinct creative concepts at a time. Rather than testing five minor text variations of the same video, test completely different angles, such as:

  • Pain-point focused hooks
  • Clear product demonstrations
  • Authentic UGC (User Generated Content)
  • Social proof and customer reviews
  • Offer or price-focused creatives

3. When to Run Dedicated Creative Tests

If you need to definitively evaluate whether a specific creative concept works, do not rely on CBO's natural allocation. Because CBO is designed to maximize overall campaign efficiency (i.e., to make money, not to test fairly), it will naturally starve unproven ads of budget.

To guarantee a fair test, use a dedicated testing structure (such as an ABO campaign or a separate testing sandbox). Once a creative concept proves its potential in the testing phase, you can confidently graduate it to your main scaling CBO campaign.

The Golden Rule: Account Simplification & Creative Diversification

Keep your account structure simple, but make your creative angles highly diverse.

A successful CBO setup does not rely on a complex web of redundant Ad Sets. Instead, every split should have a clear business rationale, and every new creative should test a unique angle of your value proposition. By reducing unnecessary Ad Sets and focusing your energy on creative iteration and conversion data, you align directly with Meta's modern delivery algorithm.