こんにちは and こんばんは only once a day per person?

Question

I recently saw a video on greetings in Japan and the guy said something that I've never heard before: "you cannot use こんにちは more then once per day to the same person". He proceeded to explain that if you meet the same person again later in the same time-frame you have to say something else - you cannot use again こんにちは.

I tried to confirm this from other sources on the net, but simply can't find anything else.

I apologize for the noob question - sometimes it is hard to tell the difference between joke and serious.

So, is he just joking (did not look like that and the rest of what he said seems to check out), or is this true?

Answer 1

It is no joke.

Among us native speakers, we generally do not say the same time-of-the-day greeting more than once to the same person per day.

Sometimes we do it twice by mistake and when that happens, a fairly awkward moment could pass even though most people would just laugh it off in a friendly way. We actually would sometimes apologize briefly for doing it a second time by saying something like:

「あっ、すいません、さっきお[会]{あ}いしましたね。」 = "Oops, excuse me! We just greeted a while ago."