i dont think its so much a matter of days rather just practice. Obviously some effects are easier to get down than others, and you will get to practice a different amount of time each time. I feel that once you are comfortable with an effect and have thought it through very thoroughly you can begin performing. However, what i do at least is practice for a trial audience. I have a few people for whom i always try new effects. These include my gf, and a few select friends. They are ridiculously critical of performance, angles and moves. They tear everything apart and are always honest with me about how well i perform the tricks ranging from moves to patter. I base my decision to perform it for layman on these reactions and also helps me know what i have to practice more. hope this helps