I've got three furballs - and IMHO it depends on the cat and/or the owner.

I have a long hair and two short hairs. They all keep themselves clean, but they can get matty or their coat can get oily(?) - kinda like when folks don't wash their hair for a while. We usually give them 2-3 baths a year - once when it gets warm, once mid summer (esp if it gets really sticky), and once in the late fall before it gets too cool. I know folks who never do it and folks that do it every other month.

Just my .02.

And no, I'm not a cat person. Go figure.