Good for my kitten, it lasts a month!
I only have a 6 month old kitten but one bag of 5kg lasts about a month! Crystals absorb urine at the bottom. When i remove stools i then mix everything as for instructions of use, to refresh the bottom part (it doesn't matter if crystals become yellowish). Retains odour well and i replace it when about 70% of the crystals are yellow.