I know it silly but we change it every day .. we have 4 cats . one is 12  he spoil rotten he's solid black and mean as a snake ...  I love him  so much 

then Mama cat she is a foster Mother Cat she had two kittens today ... There isnt male for miles but she had a call she also fostering three kittens

then their Killer she a small cat about the size of a kitten the vet said she perfect just very very small

then Crank she was born with a broken tail  it looked like a crank ..  I not creative ... 

all of them live in the house they are inside cats

we have barn cats I dont mess with them ... DH and Nephew  feed them . they are barm amimals  we do shot and we take care neuter them  and they get all shots .. they do not like being in doors . 

Well, maybe its not so silly Gayla!  Maybe I should change it every day.

How much litter do you put in it.  If you go thru a fresh box every day, then I can't.

How many inches do you put in it of cat litter.  Do all 4 cats share one box?  I heard you should have one box per cat, but I don't want two boxes!  ;-(  My place is so small, barely can handle one.

Seaturtle, you have 10 big boxes???  whow!

I also agree that I have to dump the whole thing on the weekends and start fresh, that is going to solve a lot!

Update:

Cat lovers... Buy Tidy Cat BREEZE.  It's 99.6 dust free and doesn't smell!  Some of the litters smell worse than the droppings!  Also, some of the litter is so dusty, its horrible to live with.  This is the best I can find.  I don't care how much it cost, I am using this stuff.  I think it runs me approximately 5 - 6.00 a week. 

I also dump the box once a week and spray clean box with vinager and water and I also cut back on the wet food.  Only once a day.  Now they hate me for that... but it really has helped like one of the forumites here suggested.

Now I just have to figure out how to get their cat hair under control.  HaHa like that can ever happen!

I agree dmc, quality dust free litter does make a difference!  but since our newest cat prefers doing his business outside don't go though a lot of pet litter anymore.

the only thing that keeps cat hair down is brushing at least 4 times a week lol. end up vacuuming up the hair instead!

I use Feline Pine, or rather the Petsmart store brand version, and I have very little cat box odor.  I had 2 cats at one time and live in a 12'x60' mobile home so odor control is a big one for me. 

I keep the cat box in the bathroom and everytime I go in there I check the box for "gifts".  Nice thing about the pine litter is that you can just scoop out teh poo and flush it away(maybe not if you have septic).  The pee makes the pellets break down into sawdust and once there is more dust than pellets I change the whole thing which is about a week for the one cat I have now.  There is very little dust and the only scent is that of pine wood, smells like a mini lumberyard when I open the bag.  The only problem is that it's a little track-y but a small price to pay for all the benefits. 

Not very expensive either.  A 20# bag is around $10 and that lasts more than a month, even when I had 2 using it.