Cooked turkey will keep about 3 to 4 days in the refrigerator. And about 6 months in the freezer. As with all food, the most important thing is to get it chilled as quickly as possible to limit bacteria growth. This means don't wait until the end of dinner to put food away. Carve the turkey and put enough for everyone out on a platter. Then refrigerate the rest right away. You'll want to use tightly sealed containers or storage bags to keep your turkey from drying out. Since your refrigerator is probably more full than usual, consider food storage containers that stack to save room.
Stuffing will last about 4 days in the refrigerator and 2 months in the freezer. Chill leftovers immediately and place in a tightly sealed container or freezer bag.
Mashed Potatoes & Vegetables
These will keep about 3 days in the refrigerator, but they should NOT be frozen. That's because when they are frozen, the water inside the starch turns to ice and breaks the cell walls, causing the texture to change and making the food very dry.
Who has gravy left? If you do, it will last about a week in the refrigerator. If your gravy is dairy-based, DON'T freeze it. The dairy will tend to separate when thawed. Again, it's very important to cool the gravy as quickly as possible to prevent the growth of bacteria. Use an ice bath and put it in several small containers so it cools quickly.
Cranberry sauce will last about 2 weeks in the refrigerator and up to 2 months in the freezer. Chill it in a tightly sealed container.
Finally, trust your nose. If leftovers smell funny, throw them out.