If I should forget my range finder its almost as bad as forgeting my release. Not really, but close. I'm always ranging trees, rocks, bushes, or any prominent object so if the shot comes on quick you have a reference to judge the distance. Even when I'm in the trees I've hunt out of for years I still check. The memory is not what it use to be! My sons both thought the same way as your dad, until you guest it, they missed because of estimating the range wrong. A quick story. The first time I came to Ohio to hunt in 09 I could not wait to get into the woods. I find a good tree and location. Climb into my climber get all set up. The first thing I do when I'm ready is to range in all direction. My range finder had a dead battery. All I could think of was now the big guy is going to show up. Well he didn't. I always carry a replacement battery now.