I always overpack when I travel. Not that I bring suitcases of stuff (nowadays, just the carry-on), but I always end up with items that never get worn once. So this time, when I went to visit family, I brought just a couple thin, holey undershirts (I really should replace them, but they're so comfortable and still functional) both in long and short sleeve, a patterned tunic, cropped yoga pants, a vintage plaid shirt, and the outfit I was going to wear on the plane. As it turned out, I still didn't wear everything I brought, but only because I underpacked. It was so warm in Texas. I needed to bring a pair of shorts and a short-sleeve shirt that could be worn on its own. Argh!
M's stuff took up more room. She doesn't mind being too warm, but she hates being too cold. So I brought some fleece onesies and zip-ups. She as well didn't wear everything I brought, but that was because I was desperately trying to get some use out of the many temperate-weather hand-me-down clothes she was given on this trip. Back at home, these things won't be worn much, if at all.
So still trying to figure out the perfect formula for suitcase packing. Not too much, not too little.