Chinuch Hora'ah of the Day:
I heard from the elder chassidim that in their time there was a custom that every day each person would say the kepital of Tehillim that corresponds to the years of his life [his age]. For example, if a person was 20 years old, he would say kepital 21 of Tehillim. Similarly, they would say also the Tehillim that corresponded to the the age of their sons and daughters, saying that this is a segulah that they should not go off to [take part in] a bad culture [“go off the derech”].
(Igros Kodesh of the Freirdiker Rebbe, vol. 1, Iggeres 16)