I would say here in my part of Illinois 3-4 year old bucks are somewhat common. With 5+ being pretty rare. While shed hunting I have found a handful of mature bucks who die during the winter...couldn't get healthy after the rut. My first deer was a seven year old doe. She would've needed some dentures to make it much longer. This winter could be dangerous for deer around here. 60 degrees one week 11 inches of snow the following week...all just after the rut. We'll have to see.