Continuing Rebuke

It's crucial when reproving someone about a negative behavior, to make sure the person is open to hearing comments regarding their actions.

This is especially so when dealing with an entrenched habit that may need many reminders to improve.

This can be accomplished by a one-time gentle remark about the behavior. If that is accepted and appreciated it can then be repeated as needed.

This is why the mitzvah to rebuke a fellow Jew has a double verb: "Rebuke" and if you see it's accepted "continue to rebuke".

"Rebuke, you shall (continue to) rebuke your fellow." Leviticus 19:17, from this week's Torah portion, Kedoshim 19:1-20:27

Talmud Bava Metzia 31a "Rebuke" even many times.