Again, I come back with a very basic question, so sorry! So, I had NO idea how much cat litter it took just to fill a cat box! I have three floors and read to have a box per floor, so that's what I've gotten. I had one from when we thought we were just boarding the little kitty and already went through a 4 lb bag of litter just on filling the first box and topping off, so today I bought two more boxes and a 25 lb bag of litter and filling the two boxes killed probably two thirds of it. Well, it's just one small cat, I check the boxes frequently throughout the day and scoop every time, should I do the full change and scrub to all of them once a week? How many pounds of litter do you usually go through? I've been using swheat scoop if that makes a difference.