How did I ever live without these?! Packing cubes helped me organize my clothes when I packed - socks, exercise clothes, DS's clothes, my shirts, etc. and also minimize the amount of space they take up in my suitcase. Unpacking is also easier when I arrive - give everyone in the family the cube with their clothes. :D These seem pretty well made and the zippers close smoothly. The seams have held up even when the cubes are pretty full. The large size is the one I use least, except when travelling with kids. The other 3 sizes are great for solo travellers.