When you find words like
“Adirabeh”
“Al kol Ponim”
“B’etzem”
and “Fest,” as well as questions like “what’s the Matzav?”
have become extinct from your vocabulary.
Also when you start being makpid on what brand soap or shampoo you use.(or even notice it has a name other than “soap” or “Shampoo”)
When you won’t skip a a day or two (ok, week) of shaving just because you didn’t get around to it.
and Finally when you stop taking haircuts by your friend Getzel, and learn that Jewish barbers exist outside Yeshiva as well as Jewish prices.