First of all, it’s a question of economy: a clumping formula will last much longer (several weeks), since you’ll only have to put a little back in the tray after removing the clumps. What’s more, a top-of-the-range clumping litter like ours is less dusty, so it’s ideal if you or your cat are sensitive to dust. Traditional litters are seen as more of a commodity. They’re inexpensive to buy. However, you’ll need to change it completely every week, clean the tray, then put fresh litter back in. What’s more, they tend to be dustier.