How do I turn mileage tracking on or off?

Use the Track Mileage switch in Settings → Profile. Turning it off hides the Home card, the Log Trip action, and the Mileage screen, but keeps your trips; turn it back on and everything returns. If you chose No Thanks on the Home card, this switch turns it on anytime. To erase your mileage, open Mileage → Settings → Delete All Mileage Data. This deletes it on every device that syncs with this one and can't be undone. You can also hide only the Home card with Settings → Preferences → Home Screen.