Displaying interstitial ads

These are the best times to display interstitial ads:

As soon as possible : Try to insert your first ad as soon you can in the flow of the app. This is probably the most important step you can take to maximize interstitial ad revenue.

At natural pauses in the app : Pauses may come between levels, after a failed game, or after the user reaches a certain point in a continuous game. These pauses or breaks in gameplay are generally the occasions when a user is most receptive to an ad. This leads to better ad performance and higher eCPMs.

Also:

• Avoid showing ads when a user is very engaged in your app.
• If you show your first ad at minute five of a user session, you’ll fail to monetize users who spend one to four minutes in the app.