You will recieve a wide variety of answers to such a question.

Myself...I have kind evolved to where I am at now. When I first started hunting I shot the first thing that went by. Does, button bucks, 1 1/2 year old bucks. Over time my tastes have changed. I will no longer shoot a button buck or a 1 1/2 old deer. I would shoot a 2 1/2 year old deer, but it just seems I have never had the opportunity.

Once I started being selective of what I shot, my success ratio on actually harvesting and seeing mature deer has increased dramatically. Since I may let 10 deer walk by, I have a better chance of seeing what may be the 11th deer. If I shot the first one...I may not see anything else.