gauvins

1. It is possible to get is to work all day (12+hrs) but you must use a static display (e.g. speed, remaining distance, etc.). In updated mapping mode -- which is what you'd normally want to do -- I'd say 6hrs.
2. I do not use the device's routing. I use the GPS to get turn-by-turn directions for routes planned on other platforms (I tend to use Strava). Turn by turn is excellent, HOWEVER I suggest that you turn off the route auto update feature. Otherwise you run the risk of being re-routed on a bizarre course as the algorithm strictly avoids highways, even those that you could use on a couple of kilometers to cut the overall distance in half (happened to me twice, until I was able to figure what was going on)

Excellent tool, cheaper than Garmin's full featured models that are geared towards the road crowd training with HRM/power meters, and more suited to the task than a typical smartphone. Will take a couple of days to learn how to use it properly.