A cat doesn't have to be filthy to give him/her a bath. I bathe Bassett because she doesn't groom herself properly, and she also sheds a lot. She always feels better after a bath, because she is cooler, and all her dander is washed away so she doesn't have the bad itchies. I don't bath Tilly because she really doesn't need it, and I didn't get her young enough to start her out right away. Bassett, however, was first bathed when she was about 5 weeks old. It only stresses the cat out if they aren't used to it.