We have 2 cats & 2 cat litter boxes. I've read that you're supposed to have one more litter box than you do cats, so, if that's true, we need one more box. But we don't have another good place to put another litter box.
We got our 2 cats at the same time from a rescue, & the lady who was fostering them recommended the Feline Pine Cat Litter System. However, she said to buy Equine Pine instead of the Feline Pine - it's a lot less expensive.
The Feline Cat Litter Box works like a double tray system.
W/ our previous cat, we used Tidy Cat & baking soda, & I think the Feline Cat Litter has MUCH less of a smell. It's also less messy because the cats don't scatter it.
Here's a link to the Feline Pine site w/ information about Feline Pine & how it works:
http://www.felinepine.com/
But, again, instead of the actual feline pine, we use equine pine which you can purchase at stores like Stockdales or Tractor Supply.
Here's a link to the litter box:
http://www.amazon.com/All-Pine-Self...370980&sr=8-4&keywords=feline+pine+litter+box
But, like others have said, the key really is to scoop regularly.