Ok, you have all the good advice.

I have 2 cats and 2 litter boxes. I could probably get away with one but I have the room for 2 so that is what I went with. Plus I have 2 levels and I think it is just a good idea.

Like every one else has said while Dusty is a kitten 2 is a good idea, after that it depends on how they react. After that do what you think will work for them. You could switch to just one after Dusty get older and if you start having accidents then put the second one back. Believe me you will know if one or both find one litter box unacceptable.

I treid switching to a new litter once and Bob let me know within one day that he did not like it. He came out one evening looked at me and peed all over my coat. I got the hint.