iSharing usually consumes around 1% of battery over 24 hours. So, even if you leave the app on all day, it will barely affect your phone use.
If you are experiencing excessive battery usage while using iSharing, you could update the background updating frequency setting within the app. (Please note that switching to the "Battery Save" frequency can reduce your location accuracy.)
- Open iSharing app
- Select Menu (Top left)
- Select "Settings"
- Select "Background Updating"
- Select the frequency you'd prefer