Yes, you are right. You can use it as a way to say goodbye, whether you're a clerk in a store or if you're saying goodbye to people with whom you have a friendly relationship. The only "requirement" I can think of is that the people to whom you are saying it to have to be the ones that are leaving, ha ha ha. You wouldn't say "Que te vaya bien!" if you're the one leaving his or her home to return to your place. But other than that, there is no special situation. Another thing I can say is that this way of saying goodbye is used especially if the people you're saying goodbye to are making a trip, but can be used if they're just going home or away from you for the day. And you have the uses for each pronoun right, too: "Que le vaya bien." is used for "usted", the "formal you". "Que te vaya bien." is used for "tú", the "informal you". "Que les vaya bien." is used for "ustedes", which is "you" in plural, and you say it the same way for a group of boys, a group of girls, or a mixed group. Hope this helps!

Hi, You will do better if you keep it simple, "que vaya bien" is equally correct and polite, pretty well spoken. Some times one might make mistakes that are easily avoidable. You don't need to use " le/te/les". If you're from the US "Take it easy" would be the equivalent. And It can be used in both formal and informal situations. Eme Manuel Professional teacher in Italki.

Hola Taylor. Sí, puedes decir : que te vaya bien ó que le vaya bien y sin son varios ...que les vaya bien , es una despedida casual pero se escucha bien pues estas deseando buenas cosas a las personas . Aunque puedes decir : "Adiós, que les vaya bien " queda mejor . Te invito a que sigas aprendiendo español , te puedo ayudar !

It usually means 'the best of luck to you' or 'good luck to you', but it can be insinuated to mean "goodbye'" or "farewell." as well.

Thank you, both. *Sergio, what you said about the phrase being unusual or out of place is interesting. I also just happened to notice you were from Spain but I live in southern California (US) and people here to seem to say it all of the time which is the only reason why I know the phrase. lol. Again, thank you so much for both of your feedback. :)