This set phrase implies having had the experience being talked about. It's not necessarily a negative experience, but simply one that you don't feel the need to repeat

When the journalist asked the famous actor whether he had any intention of getting married, he answered: "Been there, done that!"

Alla domanda se avesse mai intenzione di sposarsi, il famoso attore ha risposto: "Già dato!"

Dieting is your New Year's resolution? Been there, done that. It didn't work

Il tuo proposito per il nuovo anno è metterti a dieta? Già fatto! E non ha funzionato

It looks like that this expression is of Australian origin, but then it became a common catch-phrase in the USA in the 1990s through a very popular TV ad