To select the most effective search period, create two campaigns with the same settings and a different search period.
If the list has more than 10 million unique users and the campaign's geography settings are wide, then a comparison is appropriate:
- 3 days / 3-7 days,
- 7 days / 7-14 days,
- 14 days / 14-30 days.
If the list includes 1-10 million unique users or the campaign's geography settings are narrowed (for example, only the Moscow region and the Leningrad region are selected), a comparison is appropriate:
- 7 days / 7-14 days,
- 14 days / 14-30 days.
If the coverage of less than 1 million unique users or geo in the campaign is narrow (for example, a regional city or local advertising), a split of 14 days / 14-30 days is appropriate.
To make testing as efficient as possible, make sure that you have set a fast allocation and that the rate is high enough. Then expand the search period.