I would say 3 times - I never ever had a cat which needed a litter box, so having a kitten since 1 week is a new experience. I didn't even know what to do with a cat toilet. Never knew there was such a choice in litter etc etc.
I scoop in the morning, when I get up, when I get back from work and before I go to bed. I currently have a kitten box, which may be fine for some kittens, but not for one which loves to dig to Australia before going for a solid one. So I went and got a massive litter box (the biggest I could find), but as I had just cleaned the little one, before I got the big one, I decided instead of making up a new box, I would put it inside the big box.... hey presto, perfect ! I only need a smallish amount of litter, and he can't throw it out of both boxes (allthough he tries). I am quite mad with completley replacing the litter every other day, and the big box would have got very expensive very quickly.
The fist litter we bought was called "Fuller's Earth" and clumped quite well. Currently I use Supermarket Extra Value Lightweight Litter, but it's rubbish, as it doesn't clump, and I end up replacing the whole lot 3 times a day.
Next try will be Catsan. Smell-wise there is no difference. The cat is meticulous (bordering on obsessed) with covering all body movements, and I guess I change often enough.... Can't wait until he is allowed out and uses Mother Natures toilet instead !