On individual bucks, I agree. I've seen bucks that I KNEW were much older than their body conformation suggested. I have clients for whom I've been conducting photo censuses for years. And there will be a buck easily recognized by his rack. His body conformation has been saying 4 1/2 for the last three years! He just never seems to look any older.It looks easy on paper . But every deer in every enviroment does not grow at the same rate depending on multiple enviromental variables . I'd say that after 3 yrs old bucks become difficult to age in most places .
Just my $.02