I used packing cubes for the first time on a trip I recently took.  I left packing to the last minute (oops!), but was instead of my suitcase being over-full and a jumbled mess, I was able to quickly and efficiently pack everything I needed for an 18-day adventure.  In fact, I was able to get everything into one bag, leaving my carry-on for only the essentials I needed to keep with me.  When I got to my destination, I was able to unpack very easily and quickly since my belongings were already organized.  Likewise, packing to go home was also a snap & again, everything fit into my one checked bag.  So much so, that I was actually over the weight limit, but that was easily solved by pulling out one cube & moving it to my (virtually empty) carry-on bag -- that would have taken a huge effort, much digging, and re-organizing before the travel cubes.  I can confidently say I'll never pack without using packing cubes again!