How often should I bathe an adult cat?

Right now I just apply spot-on treatment (Advocate). Should I also give them baths?

Any cat shampoo to recommend?

Oh okay. So once per month spot on flea treatment is enough? No need any other maintenance for their fur, right?

Yeah they are indoor. But somehow they still get fleas.
Not sure if because the fleas come from me when I feed stray cats that camp outside my house.

Is it normal for a female spayed cat to have mood swings.

Sometimes she is very affectionate. Other times she acts like she don't know me at all. She never hisses at me but one day she cannot be away from me and demands pets and cuddles. Other days if I try to pet she runs away.