I keep my sun-dried tomatoes in an air-tight container in my pantry,which is dark most of the time. They keep really well

Although it is an extra investment, I have found that storing my dried foods in vacuum food bags does seem to help their longevity. I also store them in a dark cool pantry.

I dried my own tomatoes until they're crisp. These last forever in jars. When I need them, I grind them up and use in sauces like paprika. Very rich flavor.