If you refer to question & answer #39 on our FAQ page you should find your answer.
Keep in mind there are a multitude of variables to consider when answering this question:
1) How quickly did the deer expire?
2) How soon was it field dressed?
3) What was the outside temperature when it was harvested?
4) How soon was it put in a cooler?
5) Where in the body was the shot?
6) Was it properly field dressed and rinsed with cold clean water?
7) How long was it allowed to hang and at what temperature before processing?
8) Was it double wrapped?
9) What's the temperature of the freezer?
10) How large are the frozen pieces?
Each and every one of these points can affect freezer life. If you stick with a maximum one year rule you should have no problems. Over that, you need to make sure all areas are covered to the best of your abilites.
Dave