Similar to other cooked side dishes, baked beans will keep (covered in the fridge) for about 4 or 5 days. Be sure to reheat them before enjoying. To do so, you can keep them right in the dish in which they were baked and bring them back up to bubbling in a 350 degree oven. Or, you can spoon out the portion you need and microwave on high for about a minute, stir and microwave for 30 to 45 seconds more, depending on the amount, of course.