Do you believe that saying Yes Sir and No Sir is old fashioned? Or can it apply to now and everyday life?

My dad never insisted I call him sir, but I started to do it as I've grown older. It's just a casual show of appreciation. He's still "dad" 99% of the time, but when he goes out of his way to do something awesome for me, he get's a nice big "I appreciate it, sir."

I really think it depends on the rhetorical situation, though.