My husband and I have two cats and have had them for 3+ years, never had a problem with the cats litter boxes. He has CF, and I usually change the boxes but he will change them as needed as well (I work 12hr shifts at a hospital 3-5 days a week so sometimes I don't have time) and never has a problem. Just be careful of dupming an entire litter box all at once from the dust cloud and such but other than that, there isn't a problem.