The choice between Campaign Budget Optimization (CBO) and Ad Set Budget Optimization (ABO) isn't about picking one and abandoning the other. It's about knowing which tool to use for which job. Thinking of it as an "either/or" switch is a common mistake. Instead, sophisticated advertisers build a system where both play a distinct, crucial role in their Facebook Ads strategies. ABO is your discovery engine, and CBO is your scaling engine.
So, what is ABO actually for?
ABO, or Ad Set Budget Optimization, is primarily for testing. It’s for any time you need to guarantee a specific budget for a specific ad set, regardless of its initial performance. This is critical when you're trying to find new winning creatives, test a new audience, or validate a new offer. Marin Ištvanić made a great point on an episode of the 2X eCommerce Podcast that Facebook’s algorithm, when left to its own devices in a CBO, will often optimize for signals that don't directly correlate to sales. It might favor an ad with a higher click-through rate or longer watch time, even if that ad isn't driving purchases.
By using ABO, you force Facebook to spend a set amount on your new, unproven ad set. This gives you clean data on whether the creative or audience is actually effective for driving conversions, not just engagement. You control the spend to get the learnings you need. Once an ad proves itself with strong performance inside an ABO testing campaign, it’s ready for the next step.
When should I stick with CBO?
You should use CBO (or its successor, Advantage+ campaigns) when your goal is to scale what’s already working. Once you’ve used ABO to identify winning ads and audiences, you can graduate them to a CBO campaign. Here, you’re telling Facebook, "I trust you to find the most efficient way to get me conversions with these proven assets." CBO works best when it has strong, historical data.
Sam Piliero, also on the 2X eCommerce Podcast, calls this a "graduation program." You find what works through controlled testing, then move it into a scaling environment where you let the algorithm do what it does best. As Kevin Monell from eCommerce Uncensored has noted, CBO works incredibly well, but you have to create a history with the pixel first. Trying to test new things inside a CBO is often a recipe for frustration because the algorithm will likely favor the ad set that already has social proof and performance history, starving your new tests of budget before they have a chance to work.
How do they work together?
The most effective structure uses both ABO and CBO in a continuous cycle. You have dedicated ABO campaigns for testing, and dedicated CBO or Advantage Shopping Plus campaigns for scaling. Marin Ištvanić described this exact playbook: he uses ABO for testing, and once an ad is a "proven winner," he moves it into a scaling campaign using Advantage Shopping Plus with cost caps. He also mentioned that Facebook confirmed the algorithms for ABO and Advantage Shopping Plus are slightly different, so you shouldn't worry too much about audience overlap between your testing and scaling campaigns.
This system ensures you’re always feeding new, validated creatives into your scaling campaigns. It prevents your account from going stale. And a critical rule that Sam Piliero emphasizes is: if an ad is working, don't touch it. Don't turn off your winning ABO ad sets just because you’ve graduated the ad to a CBO. If it’s profitable, let it run.
Ultimately, this isn’t about a permanent move from one to the other. It’s about building a machine. Your ABO campaigns are the R&D department, constantly searching for the next big hit. Your CBO campaigns are the factory, mass-producing results from those hits. By combining them, you get the best of both worlds: the controlled learning of manual oversight and the powerful, automated efficiency of the Facebook algorithm.
