Packing cubes are lightweight mini-cases that sit inside your existing hand luggage. The idea behind them is that you just open your carry-on and pull out the packing cube you need (for shirts or trousers, say) rather than having to dig through your entire case.
Your clothes are also somewhat protected from spilled toiletries in your washbag -- but since one side of many cubes is mesh, it's not foolproof.
They're also not really cubes, which confused us slightly when we first heard of them, but "packing cuboid" or "packing hexahedron" doesn't have the same ring to it, we suppose.
Packing cubes are advertised as letting you separate clean and dirty clothing halfway through your trip, though we're fairly certain that the free plastic laundry bag from your hotel's wardrobe does the same thing.
Some business travellers with lots of non-clothing stuff in their bags love them, because gadgets, power cords and everything else you take with you doesn't get lost inside your clothes.
Of course, this problem is also solvable by packing that kind of item in its own little bag inside your case. Business class amenity kits and zip-up plastic document wallets come in very handy for this.
Many cubes are built with today's rolling carry-on baggage in mind, allowing you to pack the cubes and then just throw them into your bag when you're ready to go.
So what do you think? Do you use packing cubes? Are they the best thing since rolling luggage, or a ridiculous idea? Have you repurposed something else? Would you part with $25 for a set? Should we do an Australian Business Traveller road-test to see whether they're useful or useless?
Share your thoughts with other readers and let us know in a comment below or on Twitter: use the hashtag #packingcubes and don't forget to include @AusBT in your tweet!