I don't mark anything. The less scent I leave around the better. For the most part I can tell within a yard where 30 yards is, and that's as far as I'll shoot at an animal. My sight is set for 25 yards and even with a slow speed of 264 fps all I have to do is determine if the animal is within 30 yards. If so, hold the middle of the chest cavity and make my best shot. No holding high or low or trying to guess yardage. I do it this way to avoid brain overload. KISS.