Get the USB/OBD2 device instead. If your phone is in battery saver mode it will not record trips. If your phone's accelerometer is glitchy then you're super-screwed, hard breaking & hard acceleration events show up whenever they feel like. Liberty Mutual should not even offer to track via phones in the first place . Shame on me for trusting an insurance company to do the right thing, but I'm already looking elsewhere for coverage.