RE: How important is it to know....
Depends on my motive of hunting. I have spots I hunt just because of the time spent with certain people on that spot. For those spots, I don't really care if there are deer on the property..........it's about time spent in the woods with friends/family.
Now other spots I have it means everything to me to know what deer are on the property. Size doesn't mean as much to me though as age class does. I can guarantee the first full week in November (I take this week off every year) I will be sitting on property that I know holds 3.5 year old deer or better.