Cats like to be clean and groom themselves often to remove odours. They don't like the smell of urine on their fur. Cat saliva has quality of removing odours. I remember even if my stud cat got a couple of drops of urine on his breeches (he was longhair), you could really smell it, but he would lick himself....odour gone....problem solved. The only time a cat slacks off on grooming is because it is sick or in pain, very old, extremely distressed, frightened or obese.
"We humans are indeed fortunate if we happen to be chosen to be owned by a cat." -- Anonymous