I don't know what restaurants you go to, but unless you live in a town where everyone's rich, they won't be back on night 2 unless they are an extreme regular. I'm about to start restaurant work sometime in April,...
I am happy to know that someone who has never worked as an entertainer can know so much about it. I will go along with your reasoning if, by the word routine, you mean a series of 3 to 5 "tricks." In that case we have agreed. You need to know a minimum of 6 routines consisting of 3 "tricks" each for a total of 18 effects. Then you can move the 18 tricks into many, many different routines.
However if by "routine" you mean one trick for a total of 6 tricks, you are mistaken. Sorry but being a restaurant magician requires WORK and preparation, not just playing with a few magic "tricks."
I meant routines consisting of 3-4 effects. Sure, I haven't worked yet, but I think this aspect of walkaround magic should be a clear one(routining) before stepping out there to work.