I know this is probably common sence to some hunters, but how do you tell the age of a deer?

weight, physical apperance of the deer as far as does its stomach seem swollen, is its neck filled out. At least thats how i go about it.

By the date written on the freezer package!lol
I mostly just "guess-timate" by appearance/size/color. There are ways to do it by their teeth.

Your own way is fine, but a rutting buck can look pretty ragged(swollen neck) due to raging hormones and fighting. A swale in their back usually indicates an older buck.

It's not common sense. People shoot what to them is appropriate.

Plenty of info online for your reading.

Cut his leg off and count the rings.

I usually check their ID

Size of the deer compared to other deer. If it has a pot belly, slump in its back, more gray hairs than most all tell that a deer is older than others. Sometimes it can be hard to tell the difference between a 2 1/2 and 3 1/2 year old buck other than sometimes horn size.

I read the teeth way and have tried it but I was never sure.

This plus look at the legs if they look long/tall this will be a younger buck.Pot belly/arched back. big ol head, not short/thin.