Shall we try teeth whitening again?

A smiling face plays a significant role in a person's impression.
I have a habit of covering my mouth and smiling because I'm self-conscious about my yellow teeth.
Since a large portion of my work involves being visible to others, it increases my stress levels.
A few years ago, I had teeth whitening at a famous dental clinic.
The effect was good, but it didn't last long.
I'm considering whether to receive it again or look into other procedures.