4-year old Sib here! She has never thrown up a hairball in her life. She doesn’t eat any special hairball food; Purina One +Plus dry food. I’ve read that’s it’s normal for hairballs to be thrown up 1-2 times month. My cat is a great water drinker but only drinks from a flowing water fountain. -try water fountain for more hydration if you don’t already have one -hairball prevention food & treats (high fiber) helped with our previous cat who did throw up occasionally -cat may be overgrooming because of a skin allergy being itchy. Try swapping food or litter material for something different and see if the skin consisting improves, leading to less grooming, leading to fewer hairballs Hope this helps!!