Packing cubes

[HarryDresdensLeatherDuster]

Does anyone use packing cubes? I have bought a set as they seem a good idea but am now staring at a pile of mesh bags wondering what to put in each size!

Any tips please?

I like to use them if I'm using 1 carry on for all 4 of us. My suitcase can hold 4 medium size cubes. I then put toiletries in my handbag. We only use 1 pair of shoes while away.