I do it once every two weeks, but with my two, I don’t feel safe leaving them without a box for any period of time more than 10–15 minutes, and I refuse to deal with the waste of litter in another box just for an hour or two, so I just do a thorough (but surprisingly fast) cleaning with special litter box wipes, sort of like Clorox wipes. Just as good as taking it all apart and scrubbing with bleach if you do it more often, and it’s definitely less of a hassle.