So I went and put one in every bedroom like the old laundry in previous sims but when doing laundry they only empty one per load so I guess I only need one?
I had one in every bathroom but got rid of all but two, because I have a lazy Sim (ugh... townie) and let's say the AI isn't very smart for a lazy Sim, has he could be standing next to a hamper and end up putting the laundry in the one at the other side of the house...