Cats shed twice a year, in spring and autumn, and cats living in a flat with constant light and heating shed a little all year round. The autumn moult is more noticeable: the undercoat is being replaced with a winter one, and there is a lot of fur.
Why brush at all
Not for the sake of a clean house — or rather, not only for that. A cat grooms itself and swallows fur. Some passes through naturally, some builds up in the stomach. The more fur you take off with a brush, the less ends up inside.
With what
For a short-haired cat, a rubber brush or grooming glove: it collects dead fur and massages at the same time. For a long-haired cat, first a wide-toothed metal comb to work through mats, then a slicker. A deshedding tool takes out undercoat well, but it is easy to overdo: no more than once a week during the moult, and not over the same spot several times in a row.
How often
During the moult, a few minutes every day. Outside it, once a week is enough for a short-haired cat; a long-haired one needs it every other day or you get mats.
If the cat will not let you
Start where it enjoys being touched: cheeks, behind the ears, along the spine. The belly and tail are the most sensitive — leave them for later. Three minutes while the cat is happy beats fifteen minutes of wrestling: after a fight it will run at the sight of the brush.
Mats are never combed out by force. A felted clump is cut lengthwise while you hold the skin away with your fingers, or clipped off. Pulling hurts, the skin under a mat is thin, and the cat will remember.
When it is not the moult
If fur comes out in clumps down to the skin, there are bald patches, or the cat licks one spot raw, this is no longer seasonal. Allergies, parasites and hormonal disorders look like this, and a vet should be the one to sort it out.