73s or just 73

"One is never too old to learn something new" - I have made thousands of QSOs on different modes and bands with thousands of radio amateurs. Last evening, when having a qso with an "ham" in NA I get to know something new. The operator teached me not to use 73s in QSO just 73 - that is enough. Why many 73s is not as good as just a simple one 73 - that´s the question. Something like "to be or not to be", I think.
Anyway, I changed a little my macros; now there are only a simple 73, hi.