Legal Question in Landlord & Tenant Law in California

Walls generally don't suffer "wear and tear," except over a very long period of time.

Paint slowly fades and you are not responsible for that change. But if you smoked that would not be "normal" and causes a much more rapid discoloration and smell that often can only be removed with the help of paint. If the unit was freshly painted when you moved in, it should only need to be repainted after 3-5 years.