|Get this today|
She's beginning to wonder if maybe it isn't the kitty litter.
I suggested she take a look at Petco.
I found some stuff that she, and you, might be interested in.
Maybe a better kitty litter box, like this Nature's Miracle Hooded Multi-Cat Self Cleaning Litter Box. It's automated, so that should help with her time issue. She has two small kids, and the cats not being well-behaved is starting to stress her out. There is an anti-microbial element to it, to help inhibit bacteria growth.
To make things even easier, there is an indicator that alerts when it is time to change the waste receptacle. Pretty neat huh?