by Jack 'n Stans Dad » Fri Feb 05, 2010 9:35 am
This is going to be pretty much a matter of your good judgment. All of the brands of crystals change color as they transition from being completely dry and able to absorb moisture to the point of being unable to absorb moisture. The recommendations of any of the manufacturer's are simply guidelines. For example, we have two cats who share one SF, and I do a routine litter change every Sunday morning (after the first cup of coffee, of course). I've found I can not get up to 10 days with each change, but both these guys pee a lot -- so sometimes that's stretching it a bit. As a result I've just made it a part of my regular routine and it gets done more quickly -- plus everyone is happier, as we're not pushing the boundaries, so to speak.
No matter what brand of crystal you're using, the difference in color should be pretty apparent -- plus if you look in there and stir around a bit you'll see when the crystals become urine soaked and no longer able to absorb any more -- not to mention that your nose will tell you.
One thing I'd suggest is browsing my website (Foreverlittertrays) in the section on litter tips. It was put together to help people no matter which cartridge or litter they're using -- just general help to get the most out of your litter and also some ideas on ways to control odor.
Hope this helped!