As a rule, hunting familiar territory, I don't usually carry mine while hunting as I already know the distances I'd most likely be shooting at.
What I have experienced is that steep ravines will play tricks on our perception of distance when sitting on one side of the ravine, looking across ravine and judging distance to the other side. Things seem to look closer then they really are.
One of my favorite hunting spots during black powder season is situated in an area as described above. Sitting on one side of a large, steep ravine and shooting across it into the opposite hillside. First year I hunted the area, shot under two deer, never touched em.
....after checking zero on my rifle, went and used rangefinder only to find out that my guess of distance was way short.
I've set up several experienced hunters in this exact same spot. When asking them what they thought the distance was across to a certain landmark, not one was very close. Again, always short.
A surveyor/hunting friend of mine says he has trouble judging long distances in this type of situation as well.
Soooo... as a rule...on flat or gentle rolling hills, short bow hunting ranges, I don't have a problem with distances out to about 200yds. Give me an area in the example mentioned above(shooting across large steep ravine), I'd feel more secure using a rangefinder prior to shooting. Preferably, ranging landmarks prior to opening day.