I know the recommended shelf-life of home canned food is one year or less, but I would not be afraid to eat food after three years. Even food canned less than one year can be unsafe to eat. Just use common sense, check jar for leakage, unusual odors or colors, or mold. Make sure the jar is adequately sealed.
I have known of people using home canned food ten years old or more. Don't know that I would recommend it and can't imagine it was too nutritional or flavorful. (My Grandma never threw anything away. I know she consumed goodies I wouldn't have. Probably the worst thing was just the quality.)
Again, just follow common sense: store in cool, dark and dry location. Obviously, use the first in- first out inventory method. Of course, use the best quality produce to begin with. Sterilize the jars and lids. Pressure canner is the best option and I don't think a water bath method is safe for most canning especially meats or fish.
Just my opinion, but I think the (experts) often make this far more complicated than it needs to be. When I grew up everyone raised a garden and "put up" for the following year.
