When we make this, we enjoy the leftovers for a few days. Store leftovers in an airtight container with a lid. You can also leave it in the casserole dish and cover it tightly with aluminum foil. Leftover ziti will keep for up to a week in the refrigerator with the proper covering. We use the microwave to reheat individual servings, however you could add a tablespoon of water to the pan, cover it with foil, and reheat in the oven as well.