Leave enough time to modify your plan, or use at end of spend
BrandCampaign should be deployed when there has been sufficient spend behind specific ads to enable respondents to have seen the ad, but in time to be able to modify the media plan if appropriate.
We know that generally, this happens between 10%-30% of spend.
BrandCampaign can also be used close to the end of the end of spend to see how the ad performed in-market in general and whether it has legs to go any further.