Im a forester here in So. IL and for us its pretty darn close. for instance my bro shot a doe w/ his bow in early november and it was one we have been watching for 5+ years(FYI she has had 10 fawns in the last 4 years). when we aged her, we concluded she was 7.5yr old. The diet here is mainly corn, beans, wheat, and some soft mast. with the occasional acorn when we get a decent year. I not only look at teeth though, we also look at ears and eye, and overall body structure. put them all together and you can get very accurate.