been there, done that

listen to the pronunciation of been there, done that
English - English
an assertion that the speaker has personal experience or knowledge of a particular place or topic

Paragliding? Been there, done that, bought the T-shirt.

(deyim) Meaning: An assertion that the speaker has already experienced the topic under discussion. Carries that implication that the topic isn't worth further investigation. Origin: Originally, in the late 1980s, a hip use of language: now becoming less so. Later 'got the t-shirt' was sometimes added for extra emphasis
BTDT
been there, done that
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