How many job shadowing hours?

Fellow pre-optometrists,

I was wondering how many job shadowing hours you all had / if there is a general rule of thumb for how many hours you should have to be competitive? I am looking for a numerical response, something to assuage my anxiety over acceptance a bit...

On another note, if you have a heart-warming, funny, or uncomfortable job shadowing story I would love to hear it.

Best of luck during your application process, friends.