i do rescue. i have two himalayan mix kitties about five months who are soiling and will do it right in front of me. i have 5 litter pans, cleaned two times per day in the cat room which is a former master bedroom and huge. one mostly just pees on paper or fabric but never the litter pan and the other will use the box and then not, but no pattern.
i also have a five month that is wheezing, does better on antibiotics but someone told me a cortizone shot may help.
another full grown that seems to have trouble chewing and growls and shakes his head after he eats.
i can't always use a vet. we adopt out 100 animals per year and no funding at all.