Bath your indoor cat every few weeks depending on coat and coat length. Time of year is also a factor and reduces the amount of cat hair in the house. Bath your cat regularly . Persians do well if bathed every two weeks to once a month. Use a degreasing agent and soap and rinse several times to get out all the grease so the dead coat falls free during blow drying.
Regular bathing creats an unhealthy environment for all kinds of critters such as fleas and fungus.
A clean cat is a happy cat. Don't forget to clip claws before you bath. Wet hands and wet skin scratch easily.