Matzah meal can last at least a couple of years in a sealed container. Once the container is opened, it's best to store it in a sealed bag or container in the freezer.
The substance is the same, but the texture is very different. If farfel is all you have and you're forced to use it in a recipe in place of matzo meal, you should do the best you can to pulverize it...
Matza meal is matza that has been ground to the consistency of coarse bread crumbs. Matza meal is used in some cooking. On Passover especially, many people bake and cook with matza meal because it is...