The most effective way to control the number of times someone sees an ad is by:
- Monitoring audience retention metrics with YouTube Analytics
- Setting a lower cost-per-view (CPV) bid at the target group level
- Lowering bidding levels
- Setting a frequency cap
Explanation:
Frequency is the average number of times a unique user sees your ad in a position of “1” over a given time period. Use frequency capping to help control the maximum number of times that you’d like each person to see your ad on the Display Network. When you turn on frequency capping for a campaign, you set a limit for the number of impressions you will allow an individual user to have per day, per week, or per month. You also choose whether the limit applies to each ad, ad group, or campaign. Only impressions that were viewable count towards frequency caps. An ad is counted as viewable when 50% or more of the ad shows for one second or longer for display ads and two seconds or longer for video ads.
Frequency is the average number of times a unique user sees your ad in a position of “1” over a given time period. Use frequency capping to help control the maximum number of times that you’d like each person to see your ad on the Display Network.
Read more here: https://support.google.com/adwords/answer/117579?hl=en
