Whenever you purchase balsamic vinaigrette dressing, you'll want to consume it by the "Best-by" date. A number of vinegar-based sauces you can buy at the store contain different ingredients that don't last long. A refrigerator-stored dressing like this stays fresh for a year. Making salad dressings at home is dependent on the ingredients that you choose. The vinaigrette dressing you make with vinegar, oil, and some additional seasonings can be stored in the compact refrigerator for up to 6 months. Adding vegetables, fresh garlic, sour cream, buttermilk, or yogurt to vinegar-based dressing can significantly reduce its shelf life. The dressing typically only lasts a few days with those ingredients.