Learners will meet this in formal writing or speech about language, where it often carries a critical tone for unoriginal expressions.

彼のスピーチは常套句ばかりだった。
Kare no supiichi wa joutouku bakari datta.
His speech was full of stock phrases.

それはよく使われる常套句です。
Sore wa yoku tsukawareru joutouku desu.
That is a commonly used cliché.

⚖️ Not to be confused with 決まり文句, which is a set expression that may be neutral or necessary, while 常套句 often implies lack of originality.