Mimi's hair seems to just come off in the spot she sleeps in. You don't get a handful when you pet her. We brush her periodically, probably not regularly enough. Her belly has never been brushed. We're not allowed to touch it. She's a pretty long haired cat (Spencer says Maine Coon).
Anyway, never do we ever see a hairball, unless we leave her inside for a couple of days when we are out of town. Always find one then. I might have seen a dozen in the 11 1/2 years I have had her. If someone comes and lets her in and out, no problem. This is one cat that doesn't like to be left indoors for an extended period of time.