I don't mind hearing it several times a day but there is definitely such a thing as too excessive. I don't need to hear it 50 times per day, and this has happened to me before. I told the person to stop because it was too much.
I hardly ever hear it from my spouse and can't hear enough. My family says it all the time so there it doesn't mean much. But with my partner I need that reassurance that I'm loved, treasured and cherished.