If they are lightly coated with oil, individually frozen, and stored in an airtight container, they will last 3-6 months in the freezer. It's not that they "go bad," and they certainly are safe to eat even after a year in the freezer, but the quality does deteriorate over time. This is especially true when ice crystals form, but even when they don't, the quality goes down because they dry out too much in the freezer.