Regular scooping and replacing will keep the litter box smelling fresh and clean for awhile, if you are using clumping litter. But eventually the "ecology" of the box will break down and you'll need to empty and clean it thoroughly. Depending on the type of litter you use, this may be as often as every week or as long as every four or five weeks. Non-clumping litter will have to be emptied and washed much more often, primarily because urine will collect at the bottom of the box, and the odor will become very strong very quickly. Remember that if you don't like the smell, neither will your cats. (Just think of those Porta-potties at sports events.) You'll probably need to dump and wash every two to three days - let your nose be your guide.
Empty the used litter into a sturdy plastic bag and tie securely before discarding it in the trash. (Note that although some natural litters are flushable, the entire contents of a litter box should never be dumped into the toilet.)
Next, wash the box thoroughly with detergent and hot water. Rinse thoroughly, then spray inside and out with a mild bleach solution, about 1:32 (1 cup bleach to 1 gallon water). If it's sunny, let the box dry outside for an hour. Rinse again thoroughly, then dry with paper towels.
You are now ready to proceed again, starting with Step 1. (But first, see the happy cat on the next page.)