If you are, then setting a frequency cap can optimize performance and also reduce the chances of your ads becoming annoying (especially if you are using remarketing).
You can use the Multi-Channel Funnels reports inside +Google Analytics to help determine a frequency cap for +Google Ads: https://www.youtube.com/watch?v=rCSOn0tvS8c
Steps to get started:
1. Link Google AdWords and Google Analytics
2. Enable ‘Advertising Features’ within Google Analytics (under ‘Property Settings’ within ‘Admin’)
3. Enable ‘Impression Reporting’ within Google Analytics (under ‘AdWords Linking’ within ‘Admin’)
4. Check that you have a display campaign running within Google AdWords
Then learn how to find your impression data within the Multi-Channel Funnels reports: https://www.youtube.com/watch?v=rCSOn0tvS8c