My 7-year old cat has been shedding since I first got him at the shelter. As we were sitting in the "counseling" room with him and the animal person, the room was slowly filling up with hair everywhere. I was okay with it because I had a dog that was exactly the same way. The groomer used to call me at home a say that they needed another hour because he was still being brushed!!
Nigel (my cat) sheds 24/7. It isn't just shedding, it's like his fur is falling off as he breaths. When I brush him, the brush (a wire one) fills up until there is more hair that the length of the bristles. Then I brush again, and agian, and agian. After about 4 times, he's had enough, and my wrist hurts, but there is no less fur. Somestimes, if I haven't brushed him in a few days, after I do, he actually looks thinner!! Luckily, he loves to be brushed. When I show him the brush, he comes running.
I have sticky rollers in my car, in the kitchen, and a paint roller size one in the bedroom to roll the comforter. Sometimes, he gets rolled, too, and loves it, but I have to stop after 7 sheets, because he has so much loose fur. I've asked the vet about those sprays and food drops that get them to shed less, but he says to be careful with anything that can disrupt the natural process.
My little cat (T.C.) does shed when you brush her or pet her, but leaves clumps of fur all over the house, especially when the two of them are tussling. She likes to chase her tail around the scratching post, and there are huge clumps of fur up, down, and on the base of the post.
So I have a fur flier, and a fur clumper. Either way, I couldn't live without the rollers.