Packing cubes are something I never would have thought I would be so excited about - but they have changed our way of packing for the best. I first used them when taking our trip to Europe. Lots of days means bigger suitcase. I packed both my clothes and my youngest daughter's clothes in my case. These cubes were fantastic. First, you can separate items by owner but also by type. One cube for underwear/socks, another for tops, still another for bottoms. They come in a variety of sizes and are quite durable. Everything stayed organized. I use them for all my travel now. It is incredibly satisfying to open my suitcase and immediately know where everything is. Even unpacking is made easier - I loved that I just pop a cube into the cabin drawer. Done. I find that my clothes are not as wrinkled when I use them. The cubes pictured below are the ones I purchased from Amazon. They are not expensive and while not the most sturdy of cases - they have lasted longer than I had thought they would - and have kept ongoing. I like that they seem breathable and have mesh. I use them in standard luggage as well as carry-on. Trust me - you will never go back.
