Here's my opinion; watch and read all the magic you can and get a feel for what you could do. Then pick and choose. I've seen so much material on the Ambitious Card Routine, that, in the end, I just sat down and wrote out strings of material until I constructed what I felt was a routine that had good flow and was fun for the spectator. It's like writing a story, it has to have a great intro, some good filler, and a spectacular finish. I know 4 routines well. Two different version of the ACR, depending on the amount of people, one coin routine, and a miniature stage routine. That isn't to say I don't know any other routines, it's saying that those are the ones that I perform regularely. I know a lot of other stuff, that I could do on the wim of the moment all the time. Especially stuff off of The Real Secrets Of Magic and anything Jay Sankey has produced. I mean, there's all sorts of impromptu effects you can do; coin in sugar packet, sinful, stigmata... But that doesn't mean I'll walk up to people with a Soda and a quarter and say "Hey buddy, wanna see a trick?!" all day buying a new soda everytime. I guess, what I'm saying is it isn't bad to know a lot, but have routines you do on the street (if you do street) set in stone and be confident in those routines.