It starts with the tongue, not the stomach
A cat's tongue is covered in tiny backward-facing barbs, and they work like a built-in comb. Every lick drags loose, dead hair out of the coat — but the barbs point toward the throat, so the cat cannot spit the collected hair back out. Swallowing is the only direction available. That design is excellent for keeping a coat clean and poor at giving hair anywhere else to go, which is why hairball formation begins with ordinary, healthy grooming rather than with anything being wrong.
From swallowed hair to a coughed-up wad
Most swallowed hair travels through the digestive system and leaves in the litter box without incident. Trouble starts when hair arrives faster than the stomach can move it along, or when long strands tangle together instead of passing singly. The strands felt into a compact, cigar-shaped mass that sits in the stomach until the cat retches it up. Longhaired cats, diligent self-groomers, and any cat in a heavy shedding period swallow the most, so they produce hairballs most often.
How your brushing changes the maths
Every loose hair your brush collects is a hair the tongue never picks up. Brushing before the cat's own grooming session removes the dead undercoat sitting ready to be swallowed, so the total swallowed load drops even though the cat still grooms exactly as much. Work in the direction of growth, lift the coat in sections so you reach the undercoat rather than skimming the surface, and finish with a damp hand or grooming mitt to catch the fine strays a brush leaves behind. Frequency beats duration: several short sessions through the week remove more loose hair, more calmly, than one long overhaul.
Matching the routine to your cat
A longhaired cat may need attention most days during heavy shedding and a few times weekly the rest of the time, while a shorthaired cat usually does well with a weekly pass. Watch what the brush tells you: if it fills quickly after two or three strokes, the coat is carrying a lot of dead hair and more frequent sessions will help. If it comes away nearly clean, your current rhythm is keeping up. Outdoor-access cats who groom off dust and debris swallow extra material too, so a quick brush after they come in earns its keep. Keep each session in the same calm spot and at roughly the same point in the day, and most cats begin to settle into the routine rather than merely enduring it.
When hairballs stop being routine
An occasional hairball is normal cat life, but patterns matter. Repeated retching that produces nothing, loss of appetite, lethargy, constipation, or a cat who brings up hair far more often than she used to all deserve a veterinary conversation, because hair that cannot move in either direction can obstruct the digestive tract. Grooming reduces how much hair goes in; it cannot fix a system that is struggling to move what is already there, and that distinction is exactly when professional eyes should take over.
For a problem solved mainly by consistency, KinsLe's Care Teams helps by turning brushing into assigned duties for whoever is home, each one timestamped when finished so no cat gets skipped or double-brushed.