I bought one set of small, med., and large and one set of 3 slim cubes because I'm going on a tour in January that requires frequent moves from hotel to hotel.  I am somehow unable to really pack light or to live out of a suitcase without having to totally refold and repack every day. Everything ultimately gets wrinkled and it is time consuming. So I took the cubes on a "test run" on a one week trip to Paris and I will never go on a trip without them again--even where I'm unpacking for the week.  I was able to pack a "just in case they lose my luggage outfit" in the med. size cube, along with some other essentials, threw it into my tote bag, and everything arrived unwrinkled.  I packed my underwear, accessories and toiletries in the slim cubes and just popped them into a drawer in the hotel without unpacking them.  Likewise the sweaters and t-shirts in the large cube.  Packing to come home took half the usual time.  The large cube is good for a medium suitcase that you check--probably too big for a roll-aboard or other type of carry on. I thought I was a pretty good packer but I'm definitely a convert to the cubes!