Meta Ad Buying Best Practices 2024 [PREVIEW] 

But campaign budget optimization often spends on the ad sets and ads not getting the best ROAS or CPA (it can't know if your goal is ROAS or CPA anyway) and doesn't sufficiently test all your ads and ad sets. Every time I take an account OFF of CBO and turn it back to ad set budgets I find winning ads and ad sets that never got enough budget to sufficiently test when using CBO.