re: Hosted my whole family for Xmas and they left this morning and they all did laundry. Why?

How long were they in town for? If it's only 1-2 days then yeah it's weird. Longer than that and I'd probably be asking you too to use it. At least when flying, there's a difference cost wise between a carry-on and a checked bag so if you've got an available washer/dryer then I'll pack less and would like to do laundry.