I bought this upgraded box about two months ago. I have two elderly cats so their bladders work overtime. I am change out the box every 8 days or so. I bought the reusable box as I was thinking buying the crystals is good enough. It’s still easy to clean, dump in trash bag, wipe out with Clorox wipes and refill with new crystals. I do give the crystals a stir occasionally and that seems to help them last longer.  On a whole I recommend this product if not only to save yourself the aggravation of scooping the litter box daily and eliminating your home of a stinky litter box. My only wish is that the 1 inch width collection box was bigger. I think that would improve the life of the litter. I also think that it’s a novelty to see how many times you cat is using the box it’s kind of irrelevant. I suggest the regular box unless you have to track your cats bathroom frequency.