Our daily commute is 72 miles round trip. (edit: this is 35 miles motorway/highway and 37 miles secondary roads; at commuter times, we average just 32 mph for the entire trip due to traffic; on the motorway/highway, we never really exceed 60mph due to traffic) On our first test drive, I explored the capabilities of the car and was not frugal at all. Even so, I managed to get 1 mile away from home before the REX turned on. For the 2nd test drive, I arrived home with an estimated 11 miles battery range remaining with no REX used. This was with driving how I would normally on a daily basis, at commuter speeds.