CBO and ABO are about who decides where the money goes.
- CBO (Advantage+ campaign budget): you set one budget, and Meta moves it toward the ad sets with the best opportunities in real time.
- ABO (ad set budgets): you set each ad set's budget and Meta sticks to it.
Which to use
For most brands, CBO should be the default. Use ABO when you need hard control over what an ad set spends, like a fixed budget for one market.
The main risk with CBO
Spend can be very uneven, and new ad sets can get starved while proven ones take the budget. If new creative can't get spend, launch it in its own ad set and set a minimum spend limit.
More: CBO vs. ABO and why new ads don't get spend.
Related: learning phase, creative testing.
