The sooner you add the background location permission to your app, the better. This is because after an Android 10 upgrade, you will benefit from the auto-granted background location access (see #2.1 above). However, the caveat is that if a user has already upgraded to Android 10, updating to this new version of your app that includes the new permission will cause the auto-granted background access to be revoked, regardless of the app's target API level (see #1.1.3 above).