For me it is hard to age one past 4 unless he has some unique feature and I have pics. I am pretty good a 1, 2, and 3. After that I just say he looks 4 or older because I really can't differentiate between 4, 5 or 6 for that matter. If he looks 4 or older he is fair game for me. Of course I have let several of those walk to for whatever reason. I let a 180-190 lb 7 point walk Saturday, but may not let him walk the next time.