Many years ago, I took the Master Canner course through my County Extension Office. It was very well worth the time involved, and my "return" of volunteer hours was easily met by managing the canned food booth of our local community fair. The course was free and open to anyone interested (as opposed to the Master Gardening program, where one has to interview and somehow qualify). The best take-away I got from this course is to always check the USDA's recommendations for processing. You can certainly use Aunt Susie's famous tomato sauce recipe, but find a similar one USDA approved and use their method and timing. The biggest eye opener for me was that dill pickles had the highest incidents of botulism - many folks don't process them at all, or do not use a high enough concentration of vinegar.
In response to your direct question of how long canned meats will last, I think a good rule of thumb for any food processing is to put up enough for one year, and then continue to rotate your preserved goods using the oldest ones first. I make notes of how much product I used and how many jars it yielded so I can adjust the next season.
