I'm having laundry issues too. I'm playing the boarding challenge (PM me for link) and my sim's boarders are always doing laundry, when the hamper is only 1/3 of the way full. It was really difficult to do the laundry with the main sim when both the washer and dryer were running at the same time. Then, my sim has to clean their clothes up at night, put it in the hamper, but it never got more than 1/2 full since the household kept randomly doing laundry. One boarder even had the eco-friendly trait, yet they were doing laundry three times a day. Sims are really dumb sometimes.