1. I always use CBO for my retargeting campaigns. CBO does many things well, one of which is helping to guard against audience saturation, which makes targeting the overlap of social engagers and website visitors so much easier and cheaper.
2. I always start off with an ad set budget as a testing campaign for my cold audiences. When I find some winners I throw them into a CBO campaign. The thought here is to always test an ad set in ad set budgeting to control the spend more, and once it’s proven viable, give it the juice with a CBO campaign.
I have a YouTube video where I talk about how to choose between CBO and Ad Set budgeting: [https://www.youtube.com/watch?v=M4E8u_E2EZU&t=159s](https://www.youtube.com/watch?v=M4E8u_E2EZU&t=159s). The just of this video is:
1. I use ad set budgeting for testing.
2. I use CBO for my scaling campaigns/ad sets that have already proven to be successful
3. I always use CBO for retargeting, both conversion campaigns and DPA