Keep away from clumping litters and clay litters, which can be known to increase the likelihood of cancer, infections, and otherwise be bad for the environment and contain toxic properties. Look into kilin dried' non-clumping, unscented pine litter, it's the safest and best option far superior to all others.
I use Tractor Supply Equine Pine for all but 1 box. One of my old girls refuses the pine litter so she gets clay. I have found that the pine makes washing and sterilizing the litter box (which is done every change) much easier. I use less litter in the boxes since I do change it more often but it is MUCH cheaper than clay. I pay $4.99 for 40 pounds compared to $6.49 for 25 pounds of clay.
OK this pine litter sounds interesting … so how do you clean the litterbox? Do you scoop daily and replenish if necessary then dump it every so often? I have never used non-clumping stuff. So I am not sure how the scooping works with that.
I simply scoop the solids out daily and remove as much of the sawdust as possible. I do change the boxes more often but it is simple to do and not heavy. The sawdust (not the solids) is then either composted or put into the flower beds to deter rabbits. The poop is disposed of in the trash bin. You can buy sifting boxes but I am to frugal to spend the money on them.
My daughter and I are very allergic to betonite litter and anything with odor added - so we use Eco Cat wood litter. Every foster cat and kitten we had liked it immediately ... they transitioned from walnut shells ( which we liked UNTIL they added some type of scent ). I cannot use corn based litter as I store tin the garage and mice seem to like to eat it and my cats don't like pellets. I have an allergy against any type of grain so grain based is out for us. as well ... we scoop out boxes daily - more often when needed ... I like a clean bathroom and so do my cats ;-)
Tidy Cats clumping, either 4-in-1 (black lid) or unscented (light teal lid). I prefer the unscented but it seems like they keep less of it in stock (or everybody else likes it too) because they don't always have some on the shelf.
Edit: sorry, I just realized you wanted to know why. It clumps really well and I never smell anything (although, smell also has more to do with diet than the type of litter you use). I also like that it's lightweight and made from natural grass so it's less likely to be an allergen or cause sensitivities. I also believe that it is safer than clay or wheat litters that tend to be high in dust (it is the lowest dust litter I have ever used).
The only downside is that it tracks quite a bit, but having a couple of good litter mats helps a lot. I think this is probably an issue with all clumping litters though. But, I still prefer clumping to non-clumping because I like to keep track of the size of my cats' urine balls so that I can be on alert if anything ever changes in size (indicating a possible urinary issue).
World's Best Cat Litter, unscented. Outstanding odor control. I never smell her pee anymore. Clumps instantly. I can follow her to the box and scoop out her clumps into the Litter Genie as soon as she leaves the box. It lasts forever too. Eventually, I fill a fresh box and swap it out for the dirty when I feel guilty for how long the litter lasts. Her poops I scoop into dog poop bags, add a scoop of powdered activated charcoal, tie it off and store in an airtight flour jar until it's a better hour for me to run it down to the dumpster. She's often an early morning or late night pooper. I have several boxes out for her and it never smells like cat in my apartment like it did with the clay litters.
I'm in the middle of transitioning Delilah from Dr. Elseys to okocat.
I know Dr. Elseys has tons of great reviews, but I'm not that crazy about it. Despite the "low tracking", I find it all the way across the apartment (usually with bare feet). The mat quickly gets full of it. When i went to scoop it it had a lot of crumbles that the scoop couldn't get.
I decided to give okocat a try. So far I'm not noticing any smells. I only find the intermittent pellet outside the litterbox. It seems to clump ok, but its mixed 50/50 with Dr. Elseys for transitioning.
I did order a scoop with wider channels for the pellets because they don't always go through the litter genie scoop.