This is my 3rd year hunting and have always had that dilemma. How big? I hunt in TN where we have a 3/Day bag limit on antlerless and 3 bucks a season. I shot and hung my first buck last year. Not big by any means but a really nice deer; was just proud of my first. I had let 3-4 walk simply because I second guessed myself. My friend (15 years of experience) said the best way to judge a deer is laying on the ground..lol. I am still selective but I hunt public land where if I don't shoot them someone else will. I learned that last year when I watched two yearlings lay under my stand all day. I saw the same two deer butchered a week later. I hunt for the joy of hunting. The trophies will come as a bonus.