1 pile per family member: mum, dad, DD (toddler) and DS (baby).
Each pile only has 4 or 5 items so can easily be grabbed with one hand.
Your DH/DP goes upstairs, what does he do?
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Mine took... only his own pile. It would literally never occur to me to do that! I have a baby glued to me in one arm 24/7 so I guess I'm expected to make 3 trips to take the rest up. Lighthearted, and a first world problem but still!