It depends on the bottle. If you are using unfiltered vinegar (with “The Mother”), you should give it a gentle shake or swirl. The beneficial bacteria and enzymes often settle at the bottom as sediment; shaking ensures you get those nutrients in every pour. If you are using clear, distilled, or filtered vinegar, there is no need to shake it, as there are no solids to redistribute, but if there’s sediment, that’s the good stuff and you want to use it in your recipes and beverages.