Recently the plumber was working in my basement when he said he never wanted to eat home canned food because he saw so many black moldy jars of food stored on open shelves in basements. He figured that they were years old and, probably correctly, figured that they might not be safe to eat. I walked over and pulled out a jar of pears and a jar of green beans from storage boxes on the shelves I use for canned goods. He quickly said, “They look good enough to eat!”
The point of this little story is that it is important to inventory your canned goods each year putting older foods where they will be used first and discarding foods that have spoiled (hopefully there are none) or have discolored to the point you will not use them. Most canned goods will maintain their quality for up to one year. If they have been canned using USDA recommendations, they will be safe as long as the seal is not broken. However, the quality (firmness, color, and flavor) of the product does deteriorate over a period of time. Therefore, plan to can only the amount you will use within one year. There really is no point in canning all the beans in the garden if they are going to sit in a basement for several years and end up being thrown out later.
Remember canned goods stored in a cool, dry, dark place will keep their quality best.