The battery is exhausted on a good day of touring.That is about the same with recent models & new units. I always carry with me a spare battery on tours.
The routing operation is unreliable and difficult to alter (it's fundamentally useless).Allowing the GPS device routing is guess work at best. I use Ride with GPS to chart the route & save to the unit as a track not as a route. Turn Recalculation off. Tracks never change.
I allow GPS to calculate the route rarely when I need to leave the main route for urgent need.