These packing cubes are great for family travel!  I love using them to separate my clothes from my son's clothes when we share bags.  The cubes help us find essential items fast and make getting ready easier.  The cubes are fairly light weight, but do add weight to the bag.  I recommend buying different colors for different family members (my husband would say that I'm a little over the top, but he now swears by the packing cubes).  I read one reviewer that experienced the red cube bleeding; I've used the black and blue with no problems.

This particular size is good for about 5-6 shirts, 4 pants, 4 light sweaters.  You may be able stretch more shirts, pants, etc., but I don't like my clothes getting wrinkly.