The producers of these soap dramas are just beating a dead horse—all these supposed new titles are merely repetitions of the same old plot under new casts.
Examples (Wiktionary)
Cantonese
兩兜冷飯
两兜冷饭
loeng5 dau1 laang5 faan6
two containers of leftover rice
Mandarin
你真的在炒冷飯,什麼新的東西都不學。
你真的在炒冷饭,什么新的东西都不学。
nǐ zhēn de zài chǎo lěng fàn , shén me xīn de dōng xī dōu bù xué .
You're just content to stay where you are, not learning anything new.