The odor from owning a cat mainly comes from cat feces. As long as the owner cleans diligently, there won't be any unpleasant smell in the house.
Cats are relatively clean animals and groom themselves by licking their fur daily, so there's no need to worry about your cat being dirty or smelly. 
1. If the owner is worried that the cat is not clean or smelly, they can give the cat a bath once every 1-2 months, so that the cat will smell nice.
2. If the owner is diligent, they can scoop the cat litter box once a day to remove the odor. It is best to place the litter box in a well-ventilated place.
3. Over time, the cat's utensils will inevitably accumulate bacteria and dust, and will also emit an unpleasant odor, making the house smell bad. Therefore, the owner needs to clean and disinfect the cat's utensils regularly.
