If you’re concerned about privacy on your phone, and if you’d like to stop power-hungry apps from abusing their permissions by running processor-heavy tasks in the background the ‘Bouncer’ app enables you to grant permissions for applications temporarily.

With the Bouncer app, you can grant permissions for apps for a temporary period and once permission is granted, the Bouncer app will automatically remove that permission either when you exit the app in question or when a certain amount of time has passed. 

The Bouncer app is available (Beta) on the Google Play Store.