Bleaching and cleaning are different procedures. Cleaning will remove all external deposits and stains. Bleaching will remove internal stains to some extent. If the yellowish color is due to external stains and food, cleaning will be enough.

You should get scaling done atleast once a year for overall oral health. Bleaching can be done on occasions. It's not a permanent solution though. The effects of bleaching last only for a few months.

First try cleaning

Bleaching and cleaning are two different procedures with different reasons and results. Cleaning of the teeth is done by a process called as scaling and it removes the deposits on the teeth and brings out the natural shade of the teeth. Bleaching on the other hand is a procedure to lighten the natural shade of the teeth as an aesthetic correction procedure. Regards.