I've only touched slightly on the whole aging deer with teeth method. I'm trying to learn more, but I am no expert. 3 1/2 years old is what I shoot for, but I learned this year you will never be able to age bucks that well on the hoof unless you hunt constantly and see all kinds of different bucks all the time. If you are able to have sheds, photos from year to year, or even have multiple age classes of deer on your property you'll be able to age deer a little bit better. Watching all the hunting shows in the world will never get you prepared enough to age deer in the spur of the moment situation.
You can send in the jaw bone for lab aging and qdma has books and the jawbone aging chart also.Does tend to survive longer but we all know that once that buck turn 4.5 you may never see him during daylight hours and if it wasn't for trail cams you wouldn't know he was there.I have had for sure 3 bucks that I would get several pics of right after dark and find their sheds sometimes but never saw alive.I believe they just had a 14 year old doe shot this season somewhere,it had been tagged when released as a fawn in a restocking area is how they knew the age and this was one of the oldest known.